I get your concerns, but I see it in a different way. I think we are at risk either way.

I think when people are actually vulnerable is when they are using an account-based service, for free. In your example, Gmail. If Google is being a bitch about my Premium service, I will just not pay it, and move on with my life. What does someone do when Google is being a bitch to them with Gmail? Do they change their email at all 100 places they have given their email to, just to resist a small monthly subscription for example, or ads or whatever? So if talking about risk, I'd rather look there.

Wrt ublock, similar deal. They would do that anyways. It's just unimaginable that such a power position as Google's wouldn't get abused.

Bottom line, I don't see how it's a bad thing paying them when they actually offer a paid service. I rather wish that these venture capital magic money free services would go away instead. Services should have a cost, and users should pay those costs as directly as possible. The weird things happen from all the indirections providers employ.