If you can build that with AI, then 9 people with AI can probably wipe out that company, only to be wiped out by 8 people with AI…and so on.

Not necessarily. That's the old "I made Twitter in a weekend" joke.

That's not because you can technically replicate a product that your company will be successful. What makes a company successful are sales forces, internal processes and luck. Both are extremely difficult to replicate because sales forces are based on a human network you have to build, internal processes are either organic or kept secret, and luck can only be provoked by staying alive long enough, which means you need money.