This is a pretty simple concept. Similar to the infinite monkeys theorem, which says that if you give them typewriters they will eventually write Shakespeare.
Our simulation could exist to generate content, like movies, music, novels, memes. Whatever takes off here could be popular IRL.
Why does our simulation have cave art from 40,000 years ago? Because the simulations that didn’t were switched off.
As long as we keep pumping out content, the simulation can keep running. Fund the arts!