Concerning the old hardware, it's the most powerful phone which can run latest Linux kernel and the only one recommended by the FSF [3]. Specs is not the whole story in smartphones [4].
[0] https://source.puri.sm/Librem5/community-wiki/-/wikis/Cellul...
[1] https://puri.sm/posts/librem-5-4500mah-battery-upgrade/
[2] https://source.puri.sm/Librem5/community-wiki/-/wikis/Freque...
[3] https://www.fsf.org/givingguide/v11
[4] https://source.puri.sm/Librem5/community-wiki/-/wikis/Freque...
https://www.techrepublic.com/article/librem-5-review-the-lin...
https://forums.puri.sm/t/received-my-librem-5-evergreen/1087...
https://www.reddit.com/r/Purism/comments/jzj6s1/i_have_recei...
You own it. You control it. YOU have the power. That's the damn point.
If you want to play an actual game people care about and think there are game companies building those for PureOS you're delusional.
Concerning "game companies", this is a typical problem of new hardware and is quite expected (in the beginning). The difference however is that you do not have to rewrite anything, just recompile for Debian ARM and make it fit the screen. Potentially thousands of games should run well after quick adjustments.