The real goal isn't for Alacrity or Kitty or WezTerm or any other terminal to use libghostty. I think over the long term, terminal emulator user bases dwindle down to niche (but important) use cases.
The real goal is for higher-level tooling (GUI or browser) that utilizes terminal-like programs to have something like libghostty to reach for. I think this represents the much, much larger ecosystem out there that likely touches many more people. For example, Neovim's terminal mode, terminal multiplexers, PaaS build systems, agentic tooling, etc. You're seeing this emerge in force already with the awesome-libghostty repo.
libghostty would still be useful for traditional terminal emulators to replatform on, and for example xterm.js is seriously looking into it (and I'm happy to help and even offered their maintainer a maintainer spot on libghostty). But, they're not the goal. And if fragile egos hold people back, it's really not my problem, it's theirs.