Fishy. I don't see why the NES Classic would "have to" die for this. Surely both gizmos could exist side-by-side. Plus, I thought Nintendo was making a big deal out of the SNES support for the Switch.
Seems pretty self-explanatory to me... it isn't like they have unlimited resources. If they already had production pre-scheduled for a SNES Classic on top of the newly launched and highly in demand Switch, then their hands were already tied by the time the NES Classic became such a runaway success. Besides, this is likely part of a bigger plan they've set in motion to test the market for stand alone legacy systems to determine whether or not to continue the current Virtual Console model on Switch... I highly doubt it's coincidental that they've been so quiet about VC games for Switch and have NeoGeo titles on the Switch eShop without the "Virtual Console" label. What would REALLY be fishy is if they ended NES Classic production without something like this in the pipeline.
Maybe I just somehow missed that news... the last I was aware, Nintendo hadn't said a word about VC games on Switch period, let alone pledge support for SNES games. Can you cite a source? If not, are you sure you're not just thinking of the relatively new SNES VC support on the New 3DS?