In that sense, exclusives help certain hadrware manifacturers to grow their userbase. Exclusivity doesn't help the market as a whole to grow larger and healthier, actually it could be argued the opposite. Going by the assumption that every gamer has a limited budget, by forcing to buy multiple system to access all games you're actually deminishing the value of the game software market (number of gamers * thier budget), so it actually hurts developers of non-exclusive game titles.
On the other hand, exclusivity is beneficial for game studios that make the exclusive title, since they get a co-marketing push from the platform manifacturer.
Exclusivity can only be beneficial for customers if exclusive games are designed to take great advantage of platform specific features; that was the case of games designed for the Wii or DS, but imo it doesn't apply very much to the Switch or to PS4 vs Xbox One. It can make sense for next gen games that require processing capabilites above what was avaliable on older gen systems.
Looking at games released in 2020, the only one that really can fit into that category was Half Life Alyx, probably.
If a game is Switch exclusive and helps move Switch hardware and grow the userbase, then that benefits me and others like me as Switch owners because then we get more games to play on our platform of choice.
Switch owners, myself included, are getting a benefit from the fact a formerly exclusive games (from Microsoft) are being released on Switch (Ori and the Blind Forest, Ori and Will Of Whisps, Cuphead, etc.). The same way, as a PC gamer, I'm getting a benefit from the fact Sony is releasing some of their games on PC (Detroit, Horizon Zero Dawn, Death Stranding). The fact I'm enjoing these games on different platforms doesn't hinder the enjoyment of Xbox or PS4 players, so from a genereal consumer perspective (regardless of the platform I own), in the worst case I'm not losing anything, in the best case I'm getting a benefit.
Without exclusivity you could just choose the platform with the hardware specs and features you like the most and play the games you like regardless. The userbase of a specifc console would soley depend on hardware features and not depend on artificial paywalls to access specific games.
That said, I don't realistically expect exclusives to go away anytime soon since Nintendo, MS and Sony are all getting benefit from it. At the same time as consumer, exclusives are hurting me in two ways: by making me spend more money and by limiting my choice.