Amazon is a profit-driven corporation. Amazon drives down prices to gain market share and starve competitors. Then it repeats that process with different markets so customers come to rely on them for most of their online shopping (ideally also reinforced via products like Alexa, Kindle or Fire). Then they ramp up prices or lower costs (i.e. quality controls) as customers are too heavily invested to switch to a competitor for any given niche and their service range is too broad for any competitor to meaningfully offer an alternative. That's how you succeed as a corporation under capitalism at this point.

I'm not angry with Amazon because Amazon is winning at the game of capitalism. I'm just saying that maybe we shouldn't be forced to play the game because the way its rules work mean it will invariably end -- and that's something we generally don't want for our society as a whole.

It doesn't even matter whether we right now are experiencing "late game" (i.e. late stage capitalism) or not: the rules are already causing harm and literally killing people, so that's enough of a reason to want to stop.

That said, you can't just decide to stop playing if you're deeply entangled in the system. If everyone around you pretends private ownership is a thing and you don't happen to already "own" everything you need to sustain yourself without interacting with them, "not playing" means giving up access to things you need to survive.

Jeff Bezos could probably buy a private island, gather a group of likeminded people and form a commune and not have to worry about the basic necessities of life for the rest of his days. But a wage employee living from paycheck to paycheck doesn't have that luxury. Being able to exit the game without losing everything is only possible if you're already winning.

TL;DR: Regulation is good because it changes the rules of the game of capitalism, not because it enforces them.