30000 tabs is about 10x as many pages as there are in the entire Harry Potter series. Nobody remembers all pages in those series. Nobody remembers why they have 3000 tabs, much less 30000.
I noted the tab count because it's a weak measurement of memory requirements, which is directly relevant to the topic at hand.
I keep tabs because they're better in most ways than bookmarks. I'd be happy to expound on that opinion, but I suspect you're unreceptive.
FWIW, Firefox with Sidebery can handle more tabs than you or I need. Someday I'll clean them out, maybe, but I don't need to. Thanks to Mozilla, Apple, and Sidebery.
I also set the color of specific tabs (another Sidebery feature) that have some special returnability reason. I don't love the color options, nor the default ordering (would prefer the more traditional color spectrum order (red-blue or inverse) so that I could infer the tag/priority/etc from the color, but I only use a few colors and it's fine.
I don't have a problem with duplicates. If it's a page/app that I return to often, I know that and just jump to it. I'm sure I have some dupes hiding in there though. NBD.