I'm not sure if the misunderstanding is on my end or yours, but I don't see how you get "I won't use them" from my comment mentioning I have over 130 games on GOG alone. I just added 3 more. I've even played some because sometimes they give away a game I don't already have and wanted to play! But it's not a sustainable practice, it's not particularly healthy for the ecosystem, that's a problem. (Amazon's free Prime Gaming giveaways give the games on a mix of GOG, Amazon directly, Epic, or Legacy Games. I have no idea how much revenue GOG gets from the deal but I'd bet it's > $0 and it would probably hurt to suddenly go away.)
Valve doesn't feel the need to shovel free games at me to get me to use their services, they're right not to do so because their services are still the best and I'm not begrudgingly using them but happily using them. And again, especially for Linux, where they've given a great deal back to making it a viable gaming platform. For launchers, I use Lutris and Heroic to manage my non-Steam games from Epic, GOG, Amazon directly, Humble Bundle, and Itch.io. I tend to configure these to use the GE fork of proton, again something that wouldn't be where it is without Valve.
Having read your post again, it’s my misunderstanding.
But I disagree that it’s unsustainable or unhealthy for the ecosystem. It’s clearly a loss-leader designed to keep you engaging with the platform, yes, but it’s not necessarily worse for the developers or the platform than, say, a hugely-discounted Steam sale (or a subscription service like Gamepass).
Also if Steam started giving away games like Epic do I’m pretty sure they’d be adored for it.
Valve doesn't feel the need to shovel free games at me to get me to use their services, they're right not to do so because their services are still the best and I'm not begrudgingly using them but happily using them. And again, especially for Linux, where they've given a great deal back to making it a viable gaming platform. For launchers, I use Lutris and Heroic to manage my non-Steam games from Epic, GOG, Amazon directly, Humble Bundle, and Itch.io. I tend to configure these to use the GE fork of proton, again something that wouldn't be where it is without Valve.