If Code Freak can't code Pokemon X and Y efficiently to run without problems on a barely 2 year old console, then the solution is not to buy new hardware.... It is a software problem, not a hardware one...
If consoles start having 4 year life cycles and less, then there is absolutely no reason to buy them instead of PCs and Tablets... It is not worth it... The main argument of dedicated consoles is that the hardware gets support for many years...
The main argument for buying consoles is their convenience, not longevity. You don't have to bother with specs differences, drivers, convoluted setups, graphics preferences etc. - you buy a game for your system and it
"just works", that's the
"console advantage".
That's besides the point though - you have to take into account the fact that Nintendo has a long-term strategy of using
"tried and true" components in their handhelds which leads to releasing hardware on the
"low-end" side of the specs spectrum. There's only so much you can do on weak hardware and it's
not always a software problem as you claim.
Yes, their handhelds used to have much longer life cycles,
(the original Game Boy can be an example here), but today mobile tech moves forwards at a much, much faster rate - faster than ever, in fact. Within a few years we went from single-core sub-1GHz mobile CPU's to octacore ones nearing 2GHz with embedded GPU's - it's hard to keep up in this race.
That, and the 3DS isn't going anywhere. It's not being phased out, we've established that already.