Have you ever tried installing a Windows game manually with Wine? You need to create a wine prefix, install dependencies (msvc runtime, dotnet, fonts, etc) and maybe create a launcher script. Lutris helps you do this all through a UI.
It's not the only tool, and Steam does the same now by allowing you to add non-Steam games to your library and configure them to use Proton. But Lutris has been around longer than that feature, and it's fully open source and independent. It also has a library of community scripts which automatically apply game-specific tweaks to work around known issues.
False. He sees grift opportunities nobody else can.
But yeah, he's not the founder.