There was a research paper several years ago showing that the "residential IP" stuff is powered by botnets and compromised devices. Luminati is specifically called out.

Paper: https://xianghang.me/files/resi_paper.pdf Medium Article: https://medium.com/@xianghangmi/resident-evil-understanding-...

Historically, their residential proxies came from backdoored proxies of HolaVPN users.