What's to stop individual founders from setting up their "proxy" LLCs owned by them to own their stock? As LLC would be privately owned, they'd have no stock va

What's to stop individual founders from setting up their "proxy" LLCs owned by them to own their stock? As LLC would be privately owned, they'd have no stock value, and their owners could not be taxed on the gains. If LLC company does not qualify as a "corporate investor" like Sony or Tencent (from Tim's examples), is there a structure that does?