For me, my interest in Pokemon has come and gone over the years, mostly with the generations - first and second I was really into it, third I went off it, fourth I got back into it, fifth I went off it again, sixth has been more a stopgap wait-and-see generation in which I've had a casual interest but nothing has really excited me.
I really went off Pokemon at the start of the third generation as it had started to become unpopular to like it at point and, being in Secondary School, I was VERY concerned with what people thought of me. Pokemon was a hidden thing you didn't tell anyone you liked on pain of being socially excluded for the rest of your natural life. Plus the anime lost so much of its charm with Hoenn it was like a completely different show - I'd attribute that to it being the first reset of sorts which, whilst now anime tradition with each new region, was horrible that first time around - and it also stopped airing on a channel I could watch after a while, so I sort of forgot about it. It was the tail-end of the craze, and nobody was really interested in any of it around that time in my area.
The fourth gen was what really got me back into the franchise, as I'd started to really connect with people on forums at that stage of my life, and a lot of them were into Pokemon as well...and, thanks to this wonderful little thing called Wi-fi, we could trade with and battle one another. It was fantastic. The fourth generation had some highly appealing Pokemon, the anime was airing on TV again - albeit with changed voice acting, which took me a very long time to get adjusted to - and it was actually
good, and it only got better when HeartGold and SoulSilver came out. Everything felt fresh and exciting...
...and then Black and White came along, tried to reboot the franchise, and failed utterly. The Sinnoh anime ended in a disaster and the Unova anime was a complete reset which, in this case, was not a good thing. I lost contact with most of the friends I'd played Pokemon with, as the forum I was on started to go to hell and people started to leave. My interest was pretty much gone at that point and, whilst Black 2 made me still want to play the games, it's never really come back in the same way as it has since then. Pokemon has always been a very social thing for me - as a kid I was into it because everyone else was, and being able to share my Pokemon and battle against my friends during the fourth gen was a huge part of why I was so into it. Taking those connections away - and adding to that the fact that I found most of the fifth gen unappealing, especially those starters and early-game Pokemon - and it was even more unattractive to me than it was in the days of Hoenn.
I stopped collecting the cards much earlier in my life, with the Neo Destiny set. This was mostly because I was part of a Yu-Gi-Oh! forum at the time, and I wanted to learn how to play that, so my collection of Pokemon cards became fodder for me to trade. There was also what I actually got in the packs...Yu-Gi-Oh! cards had a much higher probability of pulling a shiny - hell, my first ever pack had a Secret Rare Gate Guardian in it! - and in all the packs of Pokemon cards I bought I probably got less than ten holofoils. It was depressing. Extremely so. I had a VERY limited income back in those days, and I didn't want to waste my money on a pack of cards only to wind up with nothing but crappy normals; I wanted a super awesome shiny in every pack and, whilst I did get a lot of Rares out of my YGO packs, at least they had silver lettering. It was like a consolation prize, rather than an outright slap in the face. Not only that, but I had never had anyone to play the Pokemon TCG with. Yu-Gi-Oh! was HUGE in the first couple of years of Secondary School, and going into College beyond that I at least had people to play with online. I've played a grand total of three Pokemon TCG matches in my life, all against my father, with structure decks. Not really exciting. I can't see myself ever going back to collecting those in earnest, because there are just too many of them now to make collecting sets a hobby, and I still don't have anyone to play with, so there is zero appeal there.
I doubt if it weren't for the fact that I joined PC, and the fact that I had hardly any 3DS games at the time of X and Y's release, I'd be in much the same position with Pokemon as I was when Black 2 was released: casually interested in continuing on with the games, but with little to no interest in the anime or any other part of the franchise. Pokemon is only largely relevant to me because I have a place I can discuss it with some like-minded people. I might not have the same deep connections with people I had as a teenager with the fourth gen, but I'm a completely different person now, and just talking about it - all of it, not just the upcoming games - is enough, really. Ironically, losing everything with my corrupted X file has also motivated me to get back into the games, as I've now got an excuse to in that I need to build up my collection again and make some new memories on the titles, and the anime always starts to get more interesting when the plot surfaces and the League approaches, even if we all know how it'll end. There's a lot going on and it's good to get involved in discussing it.
That said, my interest in Pokemon now, as a whole, is mostly peripheral. I'm keeping an eye on the anime, and I still buy and play the games. I might buy the odd single card off eBay if I like the artwork (I use
this as a bookmark, haha) and I only wish I could afford more plushies and other merchandise. I enjoy discussing things with others on forums. But I'm not as into it as I was when I was a kid, or even back in the fourth generation. I've gotten older and my tastes have changed, I haven't been as impressed with the last two generations, I'm not particularly excited by Sun & Moon, etc.
I can't see myself going off the franchise outright unless the next generation of titles wind up being like Black and White (forcing me to use Pokemon I don't like, having a dreadful random encounter and EXP growth rate, a hyped-up yet nonexistent story, and being visually unappealing) but, at the same time, I can't ever see it regaining what it had for me with Gen IV outside of a Gen IV remake...and I doubt that would be enough either. I suppose in that respect I'm like a lot of older fans; it'll always have a place in my heart, but I'm not so blinded by nostalgia or single-minded in my obsession that I can't appreciate other franchises just as much, if not more, than it.
As I said, Pokemon has always been a social experience for me, and I'm just not as sociable now as I used to be, and I don't have the time or the inclination to get back into the metagame when I don't have any friends to battle; just battling anyone who is willing has never worked for me. The other aspects of the franchise I've been removed from for a long time and have little motivation to get back into. So...yeah.