Currently Online 
2 year headstart I think would be the way to go, developers would not be able to "shun" Nintendo in that case because they would simply have too large of an install base to ignore.
Plus I would suggest an easy/cheap to upgrade console too, so that would prevent the urge to go buy a $400 PS5 if you can just upgrade your existing Nintendo console for $100-$200 or so.
Maybe not the ideal solution, but the best one competitively for Nintendo.
Besides I think when you get to a console that can generate like 5-6 TFLOPS of processing power, you really are starting to hit a point of diminishing returns beyond that because I don't think many devs will even be able to afford to make a game that pushes a 10+ TFLOP console to its maximum.
Such a console should be able to generate graphics like this in real time:
