It's not true of most paid, closed source software, though, while it is true for most open source software. At least in the former, the money people pay for the software directly contributes to its longevity and sustainability.

This is like saying "for the price of car, you could buy 20,000 bicycles". While that's true, I'm not going to ride my bike from Texas to Disneyland.

It's the same situation as the loss of headphone jacks and removable batteries. Some of us care deeply about those things but, antithetically to the point you've made, the market has decided that those things are no longer important to the vast majority of people.

Let's say that I created some kind of device, not as complex as a phone, but something that was like a little portable video game system or something. If the government can tell Apple that they have to allow third-parties to be able to do whatever they want to these devices, then it may hurt my business if third-parties don't have the same standards of quality as I do. Apple's standard is really, really high (insanely high by some accounts) and I feel like mine is too.

That's the only reason that I would oppose this type of legislation. The people complaining about Apple's behavior are the people that have become successful off of Apple's ecosystem and customer base. They want the benefits of having access to Apple's highly curated customer base without the downsides of having to develop and foster is themselves. It feels entitled in a way that I only begrudgingly support because of Apple's size and resources. If it was any other large corporation, I'd feel the same way. I wouldn't feel this way about any regular company, though. I would be rallying against the governance.