If LLMs are perfect there seems to be little point in any kind of software other than what humans want to use directly. There is no need for B2B SaaS as AI should just automat all of that - i.e. HR payroll, accounting, etc. there is just no need for any of that. People like video games however so that will still exist.

Of course there all kinds of discrete points between the current situation and "perfect LLMs / AI".