The problem is context. I think Tab Groups partly helped. But the implementation of tab group is still not good enough as it is. A lot of tabs aren't bookmark but unfinished work or research. I currently have Groups for Housing Market because of Rent increase, Jobs Search, Product Research, Marketing Courses, Surgery Research for Lasik, Youtube and a few others personal stuff. I wouldn't be surprised if it add up to 500 tabs.
Again, I will take this opportunity to say again, Multi / Lots of Tabs on Safari sucks.