But that's my point, tabbed browsing is ubiquitous and so efficient.
I'm genuinely surprised that people would rather save one source at a time, by clicking a button once, and then moving onto the next one, when they could be saving 5+ with a single click instead.
As for @dragonfly's automation idea, I'm not sure how you'd know from a non-browser-based script how many tabs you have open, but if you could figure that out, you could trigger the save button with Cmd-Shift-S/Ctrl-Shift-S, so you could do this with a program like Keyboard Maestro on macOS. At the very least you could set a macro for go-to-next-tab-and-save-to-Zotero.
need a clean Firefox for a presentation but still have some important tabs open
or you'd have to open a new window first, which I suspect most people never do.
People save multiple search results to Zotero using the folder icon.