If they drive on fan demand, money, and all that other stuff, then a remake would've happened a long time ago.
Not so true, I believe - firstly, games take time to make - a lot of time. Secondly - Nintendo has the way of releasing only one core Pokemon handheld game every so often, so that maximum sales can come from it - otherwise if they wanted they could have easily made one and a million other games if the above weren't the case.
Anyway - Nintendo is a company - their main drive IS money. If a game sells, they will consider making it. If they deem it will not sell well - they wouldn't make it.
Plus, making remakes of a game only a few years old would be pointless - look at FR/LG and how long it took for them to make it after the original RB. It's now about that stage for GS, so they could do it now. Or maybe next gen. Or not at all, of course. But last gen - there was really little need as they already had 5 major games nicely spread along the timeline of the 3rd gen, along with two console RPGs and many spinoffs. And Johto Pokemon were readily available in FR/LG, and Colo/XD as well, limiting any real need for a GS remake, particularly as GSC was in the previous gen and all. Remaking a game that 'old' would limit sales out of it, for instance.
Now though - it's around 10 years now. Majority of the GS games no longer work thanks to an internal battery problem. And some 2nd gen Pokemon aren't yet available in 4th gen games along. Every Pokemon is practicularly available from 3rd gen games - yet despite the inclusion of the Kanto birds and the Regi trio in Platinum, 2nd gen legendaries have not yet been made availalbe in 4th gen games.
It may not happen, of course - even if they deem that it would sell, it doesn't mean they will make it. But there is a logical opportunity for it now, and things like the many references, to actual unnecessary game coding, to suspicious Johto Starters inclusions in the new movies... it does show that they have considered it seriously - for why else do these things? It's certainly no indicator that it will happen, but it's certainly more than anything beforehand. We'll have to wait and see if they do do it though - but I don't see any reason to discount the possibility of it happening. =)