Thanks to the magic of the middle mouse button, I always was a heavy tab user, opening "sub-tabs" in the background for plenty of link-heavy sites (like HNews). In the early days I created lots of top-level windows and used Expose for switching between them. After discovering TreeStyleTabs, I became a one-window guy again.
So it seems I'm in the tab camp. But there's still the question why I need to have that many tabs open in the first place? It's not like I'm heavily multi-tasking. There's a good reason for opening those three zeit.de news articles in separate tabs, but why do I need to retain the tab group with 13 react-redux links or 27 interesting CPAN modules?
We've got a problem with browsing history. For long-time storage, there's bookmarks. I'm using pinboard for this for unified access and tagging. But if I file something there, it might be that I forget it, so I keep a tab(-group) open.
Heavy tab users seem to be closer to using them as TODO items than mere window management. So it might be a good idea to look at TODO/GTD/Calendar apps for improving the stats quo. Not just filing vs. on-screen, but different levels of priorities. Maybe a bit of "AI", where Clippy reminds you that you've got a tab-group stored that contains this exact Stack Overflow article about handling NULLs in Oracle. And from there, you have quick access to the browser history "surrounding" those pages, even if it was a year ago. A "mega-expose/Jurassic Park file explorer" view of saved tabs/bookmarks, where you can drill down by tags, text etc.
The tech wouldn't be the big problem, probably doable with browser extensions. But getting a good initial design for this is the difficult part.
And then you find out that some Hypertext paper from the mid-70s already had all that.