If two platforms share compatibility then developers can choose to target the weaker system and release on both.
For some games this might involve a bit of compromise and cause resentment with the owners of the more powerful system, but for other (simple) games it might not involve any compromise at all.
Either way there are a lot of Switch consoles in the wild and there will be some publisher support for the Switch for a few years yet.
As an example from the other side of the fence ps4 is still getting titles:
This gamesindustry.biz article is offering less info and context than the press release it is cribbed from.
https://gog.prowly.com/375292-gog-joins-european-federation-of-game-archives-museums-and-preservation-projects-efgamp-expanding-its-game-preservation-efforts
I’ve never heard of EFGAMP, have they weighed in on the Stop Killing Games campaign?