Why's the S24 Ultra's development so bad?

Hey everyone,

Back when I rocked an S8+ and S9 Plus (still using the S9 next to S24 Ultra!), I'm curious where all those custom ROMs went. My S9+ has something like a Pixel ROM, but I can't imagine that on my S24 Ultra. Are those ROMs only for base S models, or is custom ROM development just dying out? Most S24 Ultra ROMs are just slightly tweaked stock ROMs.

Thanks!