What if I signed up before those ToS said they could use my data in this way?

Oh right, companies change ToS and EULA and "agreements" without notice, without due process, and without recourse.

I have no problem changing how I use "their" data in such situations.

That doesn't actually mean anything

No one likes paying taxes but they still do it. They could just not work and not have money and therefore not need to pay tax.

I didn't want the web to turn into monolithic platforms. I abhor this status quo.

You cannot function without these enterprises, but that doesn't mean they're ideal or even ethical.

Microsoft wins because of network effects. It's impossible to compete. So I think it should be allowed to assail their monopoly here by any means. It's maximally fair for consumers and for free markets.

Ideally capitalism remains cutthroat and impossible to grow into undislodgeable titans.

Even more ideally, this would become a distributed protocol rather than a privately owned and guarded database.