Was it, though? My memory isn't perfect, but I seem to recall the days after Instagram copied the video feature, there were articles on tech blogs mocking Vine on how Facebook was going to eat their lunch. You could even refresh your browser on Vine's Twitter page and watch the count of its followers decreasing in realtime. Not pushing back, I just remember it kind of petering out in popularity (in the US, at least) and then quietly going away, and everyone sort of shrugged.
The 6 second limitation was holding them back and their competitors knew that longer formats would be more successful. The vine 6 second format was interesting and kind of "created" the format that turned into tik tok, but there is no doubt that vine would had to have pivoted sooner rather than later. Still, the decision to shut it down was shocking and short sighted.
