he's getting that much money because his project looks interesting, that is what most developpers want, so they are willing to take the risk
now other language designers need to learn from this project
keep your language simple, keep dependency list tiny, make clean syntax, focus on efficiency and small file size, and you win patrons
but people often then bloat their project, with uneeded features, that makes language harder to read, and harder for tooling to support it
edit:
i love Zig, i'm not using it, but i plan to once package manager is ready and vscode plugin with autocomplete and debugging is available
please make it happen, open bounties if you can't