My two cents: The human behavior on tabs is surprisingly akin to garbage collection. Therefore I think we need some solution inspired by the incremental, generational GC. Gradually disappearing tabs may be such solution, for example. Many tabs are created in a group, and such group is garbage-collected altogether; pinned tabs behave like a statically allocated memory; the GC has to be able to determine if the tab is created in the context of other tabs or it is independent to others; if I don't want tabs to be disappeared then I can go to the tab for the extended period to signal the GC not to hide this tab for now; etc.