Please make your own topic if you have your own issue. We can understand you experienced something disappointing, but anger shouldn’t make one negate a different discussion.
It is in the sense it is advertized (file sharing through Trimble Connect, one oculd indeed argue about that), but not in the sense of simultaneous editing.
I didn’t even say that. But it depends on the browser as a runtime, and through the years browser tabs used to crash at phases (when Chrome/FF introduced fast release cycles; when Mozilla introduced multiprocess and tab isolation; nowadays when out of memory which is common in SketchUp for Web). We are seeing that in the forum.
So this is your issue. Have you tried “undo”? I would expect after an autosave, the undo stack is not reset to zero, but lets you go back before the save. If not, this clearly needs to be reported as bug.
If the browser crashes, this could indeed be a problem: The autosave function does not save the undo stack to for undoing temporary operations. Maybe autosave should not overwrite the manually saved version. There is supposed to be a revisions list in Trimble Connect that is for this purpose (though I cannot find it).