I don't know that all that really makes sense to me.
1) Most people do not have multiple accounts, or at least do not care about those accounts being linked. And if you are in that situation, then you are (hopefully!) already being methodical about signing out and clearing cookies (or using a separate browser profile, private browsing, whatever). And if you aren't being methodical about this, eventually you are going to screw up anyway, no matter what the login flow or session timeout is.
2) Again, if you are worried about this attack vector (and, also again, most people probably are not), then you should be methodical about immediately signing out and clearing cookies when you are finished doing whatever you are doing. Also again, if you are not doing this, eventually you are going to forget, and succumb to an attacker.
3) Absolutely agree, but I don't see what this has to do with the persistent login issue.
4) It is indeed your computer and your data, but it is not "your" account. It is access to a remote computer system that someone else has granted you, and it is perfectly within their rights to decide how that access works. You may not like it, and that's fine: you are perfectly free to use a different service[0]. I think there are many reasons to claim that Google is a monopoly in some area or another, and that opting out of Google isn't feasible for some people, but "I don't like the login flow" is certainly not one of those reasons.
[0] Earlier this year I dropped GMail and moved my mail elsewhere, and I stopped using Google search several years ago. I've also stopped using Google's OAuth service to sign into other third-party websites, and have switched to regular email+password for any sites where I'd already signed up for an account using my Google Account. I'm working on weaning myself off of some of Google's other services, but I will admit this takes time and effort, and I'm not always up for the work involved. But that's on me, not on Google.