1827 tabs here - I have a problem. Firefox devs, if you're listening, an "automatically clear tabs older than 30 days on close/open" option would be highly desirable for me (and maybe those like me).
I also recently closed ~8k.(Yes, mostly HN/lobsters/news and usually things I found interesting in the past ~6 months)
For firefox users: there's a nice little addon called LoadTabOnSelect3. Without it firefox crashes to the point where you can't recover a session if firefox tries to impossibly load thousands of tabs on a machine(ram amount is irrelevant).
The feature you're talking about is found in many addons, I believe also in the one i mentioned. Don't hold your breath waiting for Mozilla to implement good things quickly (though they're much better in that regard than Google: which removes features and makes the web experience worse)
Funny that I will hoard an entire window with dozens for weeks, accidentally lose it one day and be like meh.
For bonus points, I'm pretty sure that option exists on Firefox for Android