It's not laziness. I typically run at least low hundreds of tabs open, frequently up into the low thousands. I know I've cleared 5,000 before, but I'm not in the business of tracking too closely--I'm just not interested in how many there are.
Bookmarks are not the same thing as open tabs; a site can vanish but still be available in browser cache/memory. A bookmark may help you find a page you were on earlier, but it's hard to know *why* you bookmarked it, to organize them linearly, and to distinguish between an ephemeral interest and a permanent reference. Really, bookmarks are a vestigial feature of the pre-Google web. Do you remember when we all had "home page"s that given over to collections of links to commonly-used sites? That, too, has gone. In my case these have been replaced by tabs.
It's all part of an efficient workflow. I see people do something like: Google search, click a result, read some of it, click back, click the next result. This pattern is inefficient and drives me nuts; when I do a search I scan through the results and open anything that seems helpful new tabs--I may even refine my search a few times and open some tabs for each variation--, then I C-tab and begin to review. I can go from zero to 20 tabs in moments without even noticing it, then I read through them and close tabs that are irrelevant. When I get to the end of the subject I am researching I'll close most or all; I may leave open a tab with an answer or something I need to refer back to as I go back to what I was doing. With news it's the same: I open in a new tab each story that I want to read more about. I may not read them all the same day, but I leave the tabs open as a linear queue of interest and get to them eventually. It often happens that the queue grows faster than it shrinks, and that's fine. I come back through later and close out unread tabs that no longer seem interesting.
I can't imagine *not* doing this. It's not lack of window management; I currently have 11 browser windows open and they *each* have dozens or hundreds or thousands of tabs. It's *not* laziness. This is simply a way to organize information that maps well to the way my brain works.
The day that Firefox removed tab groups was a sad day indeed. There have been few tab management features which actually improved my ability to organize, but that was one of therm.
