I mean, we can dismiss everything as hearsay at this rate and the conversation will keep going around in circles lol.
Being on GP helps developers from not just the exposure related sales, but also development assistance, the same applies to PS+ to some extent, but we have more reported comments from indie developers on game pass on the matter so it is what it is.
As
Fess
pointed above, indie games don't generally sell a lot anyway, and the onus is not on gamers to need to buy every indie game, but subscription services like GP are a great way for players to play games they would otherwise not have considered, which can lead to additional revenue for the developers as gamers can then either buy the game, or additional content for it.. that's money that was not going to be spent in the first place.
On the topic of Furi, is anyone really expecting a game from 2016 to get a notable bump due to DLC in 2022/2023 anyway ? Very likely not.