Nintendo is "greedy" no doubt but I think the remasters/ports have more to do with the opportunity that rises from a lack of backwards compatibility than anything else.
See if the Switch was backwards compatible with the wiiU, I highly doubt they would make as many ports/remasters because people can get the wiiU version and will get very similar visuals/experience with a lot of these remasters/ports. It's similar to the lazy ports/minimal effort remasters which were on ps4 and xbox one. They have had a ton of remasters/ports due to the lack of BC. But now with the Ps5/SeriesX, because of BC, they will have a lot less ports/remasters from the ps4/one era. Especially since Sony and MS are practically giving a lot of these games away through PS+ Collection and Gamepass.
Imo if Switch 2 has BC to Switch, I doubt we will see as many ports/remasters of switch games compared to the wiiU games to the switch regardless of how successful Switch 2 is. Assuming they don't call it the Switch U that is...
One has to wonder just why these consoles were made without backwards compatibility...
To be fair, there are a number of technical reasons as to why BC wasn't done for Ps4/X1/Switch.
Now sure, if they put enough effort behind it, I am sure they could have given an option one way or another. But I can't fault any of these companies for going the "lazy" route instead of spending R&D money on a feature who's purpose is to make them less money and generally isn't the main decision maker when it comes to console purchases for most people. Cause imo, because of the drastic changes in architecture, it wouldn't have been as easy as compared to say ps4/x1 > ps5/series x.
Now if they didn't have any BC for the PS5/Series X and Switch 2 (assuming Switch 2 has a similar architecture as Switch), I would certainly facepalm at that point.