Use Android

That is the user's solution. Patreon (the company having trouble with Apple) is not in the position to get ~50% of it's users to use a different phone.

Apple should not be allowed to be in the middle of business and half the users of the world.

And yes, that is very much something that governments have regulated for decades. In fact it's basically why anti-trust was invented. Train companies and deals with Standard Oil meant together they controlled the market since if you didn't go through them you couldn't ship your product.

Android is actively in the process of trying to kill off the ability to install your own software that is not Google-approved, so this is temporary solution at best.

That's only a solution until Google does the same. And then we're stuck. What do we do when the two largest phone platforms perform this stuff? Go off the grid instead of talking to our representatives?