You're oversimplifying things. To begin with, every game so far has added something new. The obvious changes come in generation shifts, but if we look at the other games and ignore the small QoL changes, we can see non-trivial changes.
Most of the third versions introduce a lot of graphical changes - full animations, new maps altogether, form differences, map tweaking, etc.. From Generation VI onwards, we enter the realm of full 3D which means things get harder to edit in a way. Some also introduce full blown new features like the Battle Tower, the Battle Frontier, Amity Square, Join Avenue, and so on. Others still will rework the plot since the originals relied a bit too much in the box legendaries.
The remakes need a whole new set of maps, trainer roster changes, movepool changes, TM changes, sometimes full blown features that weren't in the original (like Pokéthlon, the Sevii Islands or the Delta Episode)
It's easy to miss these changes since they're not big or flashy, but there's a lot of them and that stacks up rather quickly. And when you consider the small teams involved in the project, any change becomes slower simply because there are less people to do the boring work necessary for them.
Whether those changes were needed or appreciated is different conversation. But they are a lot of work and they are not easy to do.
Now, I'm not saying that GameFreak is perfect. For example, Gen 6's Sky Battles haven't been a thing for 8 years, but they're still mucking up the design of non-grounded Pokémon to this date.
But I think it's important to keep in mind that until Pokémon has a development cycle that's not exactly very common in the industry. Often there'll be two games being developed in parallel (that's why HG/SS had Pokémon following you but B/W didn't), the teams are considered small by industry standards, the games are almost always released in two year cycles.
We have to see how things will go with the massive DLC system that Sw/Sh is introducing - this could be a "gamechanger" in a lot of ways, since it could make Pokémon games more of a rolling release and introduce a lot of those optional features like difficulty settings, level caps and so on with less strain on the team -, but in general a number of the massive sweeping changes that have been voiced in this thread just can't happen unless the structure of that development cycle changes. A number of other changes can't happen unless the design philosophy of the series changes. Both of which, unfortunately, aren't very likely considering Pokémon is the biggest media franchise in the world.
I don't care for sword/shield or the idea of using dlc releases to constantly patch or change existing games. I prefer the old ways a game's made stuffs in it, and that's it, you get what you pay for and it doesn't suddenly change 2 months down the road.
I can't remember if I wrote this in this thread or not, but I'm just fine with how the games are, as long as we're able to go in
and make whatever changes we want I'm almost completely satisfied.
If I don't like a move, I can change it, don't like difficulty I'll make it harder myself.
Emulators and romhacking have already "saved" pokemon or me.
and for the whole pokemon following you thing, heart gold and black and white are in two different generations, and
unfortunately I couldn't get the gold/silver remakes so I forgot that was even a thing, but in black and white,
I think they started experimenting with 3-d or psuedo 3-d graphics and that messes with a lot of things.
The follow mechanic is already hard enough but carrying that over and making it work with 3-d and perspective shifts?!
I'd say no wonder they dropped it between generations, you can look at sword and shield to see how that could have gone.
For example certain mechanics are already broken by the 3-d in black and white, for example I have an action replay code setup so I auto run on a toggle, whenever there is a perspective shift this stops working and I have to press and hold the button myself.
Ok now that aside...
Yes everything you said is true, and I don't want to start an argument about this, I just wanna enjoy my time here.
I was talking all within each generation, like gen 3 for example, we have the first entries and then the remakes, ruby saphire, then emerald and fire red and leaf green.
Then gen iv, we have diamond pearl , then platinum and heart gold and soul silver. (though later did have much more difference in mechanics and features)
Looking at the code for the games all the sprite and move data is there already, even for pokemon you can't access without events or moves that almost no pokemon can learn.
Me just one person on no budget, could add new maps by copying existing ones and making small edits or pallete swaps.
Could make new legendary events by writing a few scripts, some movement commands, and using sprite data to make them visible.
And I could probably make a new battle frontier by copying the existing data; trainer data, maps, menu's etc, into another game and then just repoint so the game can recognize and access it all.
Then edit the teams and map location till its unrecognizable as the old thing.
Presently I don' t have the skills or experience needed to make those changes or to do them swiftly but if I did,
I (one person not just linking this to me specifically) could make all those changes within the time frame of a couple years. Working every day of course.
I doubt their teams for these games are in the single digits, so I just think they don't need anywhere near that amount of time to actually complete the game (or a game pair). Again assuming this is all in one generation and they don't have to add anything major mechanics or animation wise.
Mind that, all time frames are just based on a combination of my own experience making basic edits, and some knowledge of the lifespans of some of the more successful romhacks in this community, and knowing how small their teams were, if they used a team at all.
This is just my opinion I could absolutely be wrong.
