That's not what you claimed, you said Valve killed the used PC games market. Valve made a system where selling old copies is not currently viable/popular. You can still buy physical PC games, and you can still sell them. Finding used copies is hard, though- but great news, before Steam existed, finding used PC games was still hard. In fact, it is now arguably easier to find used PC games on the internet.
Ok, I admit that this is what their fans do, not Valve itself.
I've never once heard a claim remotely similar to this, sounds 100% made up
Are you saying you can ignore Steam updates or game updates now?
Always could.
Every one of your bullet points is an extreme stretch. The only one I could see as a negative- instead of just you making good practices sound evil- is selling accounts. But they ban the selling of accounts due to other legal ramifications. It isn't unusual for any site to ban the selling of accounts.