This is how I discovered Safari on iOS has a hard limit of 500 open tabs. Rather horrifyingly, when you try to open tab number 501, it asks if you want to close all open tabs.
Even with the fancy mobile interface you really just need to store a thumbnail (plus the URL and title) for each tab, and even an older iPhone should have little trouble scrolling through thousands of tiny images.
In Chrome I use a tab suspender extension, in part because there was a bug that bit me alot where it would leak memory of you leave a tab active with a highlight. Don't know if the bug is fixed yet. Tab suspending makes my Surface Pro run better; seems like it shouldn't be needed.