What if they put this warning up to their (actual) customers, like the US insurance companies that could hike premiums or ditch their customers before they realized they had costly conditions.

I would be quite likely willing to pay Google for their services more than they are making out of me currently, if:

1.They agree legally bindingly not to give any of my data to anyone.

2. They do not show me a single ad anywhere.

Obviously, that would mess the current business model of everyone counting on adwords revenue, so I am not holding my breath here.

They would quickly have a potential revenue ceiling that would likely decline over time.

At the moment it's the opposite.

Google is trying this with their YoutTube Red, which removes all advertising from YouTube.

I believe it is actually kore profitable than advertising. With ads, an average person is worth between $0.01 and $1 a month (depending on what type of ads), much less than the $9 for YouTube Red.

I had an humorous image of that information being relayed to you by Clippy.

You appear to be writing a hacker news comment, do you want me to really fuck that up for you?