I'm not the person you're responding to, but I would say unequivocally and unironically, yes! The end result is more competition, lower prices, and more options for the end consumer. Sure the raw idea of this mechanism is a little naive and could be refined, but the outcomes you paint sound totally reasonable to me... think of this as a creative way to apply a new kind of tax to the criminally undertaxed big tech behemoths like Amazon and Google.

If you come up with a cool service on top of Amazon's API, should Amazon be allowed to use your APIs to scrape your service data and use it in their offering?

If you get above <threshold> users, sure why not? It doesn't have to be free, maybe some sort of auditing service could determine a "fair" price. But it would be open without the possibility of shutting it down in the future unless maybe Amazon themselves ditches that API internally.

You are allowed to do that(as far as I understand scraping legality), but google/amazon/facebook are also well within their rights to blacklist your IPs, or implement other methods to prevent scraping of their IP(intellectual property in this case).

If it’s so I can access my own data then yes is should be able to.

Google isn’t remotely comparable, and I believe Amazon has APIs for their store fronts / merchants (still can’t access reviews you leave)

Amazon is infrastructure at this point. Everybody should have access to it. Jeff Bezos won capitalism, give him a medal and let him explore space.

Why do we treat government services and certain large private services separately? Why are government publications public domain, private publications not? Why does free speach apply to the government, but not to corporations? Why can't we treat amazon like a utility?

I believe the difference is because in the past people fought for these concessions from the state. They decided for example it would be sensible that the government should not restrict free speach. And before, they decided not to take feudalism as a given but to democratically elect their government. I know I'm being a bit dramatic, but there's no reason people couldn't get together and demand these kind of concessions from powerful corporations, too. Access to Amazon's product API is really the least example of what would change.