Tor/onion routing integrated into Firefox would be great (even if you could just securely connect to dot onion sites via Firefox).
so long as open source software is a thing and developers have the capability of being anonymous, there is hope for the future.
It can't be shutdown now but it could be heavily controlled to an extent where it might be.
There's often going to be lingering software vulnerabilities that could be exploited by anyone wanting to kill your privacy as well as things like the repositories for tornado cash being closed and wiped a few months ago in the news (there's likely backups but it might be hard to work out how trustworthy they are - especially if lots of maintainers use remote management systems for storing and accessing their code thst are all hosted by companies one government can control).
Even if they don't, someone else could likely sell your data. People's behaviour patterns likely aren't hard to predict and spot, if you go from.not using a vpn to using one, you can't expect to be well hidden and may take more risks as a result.
I'd trust a free vpn as much as I'd trust a paid one though (paid services will just have highe rprofit margins when they sell your data).
There's probably going to be little in the way of ads when they get rid of that sort of thing. They'll probably do like a lot of companies seem to and tell you they're updating their privacy policy, give you a few weeks for it to come into effect and you to get annoying of hitting "remind me later" and then they'll get a lot of data to sell. It's also not like you'll spend $1500 on a phone only to decide your privacy is worth more and buy something else - I expected them to pull their privacy thing long before this time though.