The answer is in the comment you just wrote.

If those tiny startups are successful, they will become the next bloated large companies where things take forever because of "intra team conflicts, legal hurdles and processes", which are categories of things LLMs will never solve because LLMs can't solve problems of human consensus.

If those startups aren't successful, they will run out of money and die.

Big companies take forever to do things because they have lots of paying customers to keep happy, a bunch of people who are ready to sue them at the slightest misstep, thousands of employees with families who want job stability and therefore don't want to be betting the farm every 6 months, etc.

Tiny companies can iterate really fast because they have none of this.

LLMs don't change anything about this fundamental reality.