Well, I mean, I can see having maybe 4 or 5 tabs. FOUR or FIVE. Not "Seven Thousand."
For "Seven Thousand", you are better off with a properly sorted and manicured (eg, with dividers, and nested trees) bookmarks file. You need that ONE page out of your seven thousand you want to keep track of, you can just click 3 times to get it, always, 100% of the time. No Kvetching when something closes the tab.
The reasons for this are multitudinous, in that inactive tabs **ARE NOT INACTIVE**. They are still consuming bandwidth, are still processing javascript, are still displaying ads (if you dont have an adblocker), are still processing cookies, and in many cases, are still actively monitoring your browsing experience.
You should close that shit.(tm)
Even on android, those tabs are still "Doing shit" when you are not actively viewing them. This is true in both android chrome, and android firefox. The browser will start running the risk of being murdered repeatedly by the zygote process reaper if it gets too unwieldy. For all the reasons above, it will also destroy your data allowance very fast. --Not to mention what it does to your battery, given that javascript is still being processed. Sometimes LOTS of javascript, because of how heavy cross-site javascript tends to be these days.
There are a shitload of reasons to just Close That Shit(tm).
[I have a rooted android phone, so I can make a video about how this is true, by spying on the browser's user process with TOP over an ADB host connection {as root}, then opening and just ignoring a shitload of tabs. I might also add the zram process to the list of monitored tasks, since most modern phones use zram swap, and under memory duress, the phone will make heavy use of it, which is CPU expensive. It's been awhile since I have done a youtube video... I think I'll do this!]