> I've seen multiple examples from social media in the last month of people scrolling through their mom's (/little brother's/etc) phone, showing hundreds of tabs, but usually all duplicates of the same dozen or so.

Honestly this is the only reasonable way to use tabs on a mobile browser. There is almost no drawback of keeping them and closing them is a chore. I get it sounds like the typical "boomers using the internet" but given that you should expect old inactive tabs to unload anyway having even hundreds of tabs open is a detail.