Vimeo never seemed to figure out what they wanted to be.
Did they want to be a white label video hosting provider? Did they want to be a social media network? Did they want to be prestige TV for the online age? Did they want to be IFC (indie movies) for the internet?
If they had picked one track and stuck to it they would have done a lot better but they ended up at the intersection of all those disparate spaces which ended up being a very tiny place.
They had several opportunities to become a legitimate competitor to YouTube with the number of times YT dropped the ball over the past decade but they never made the big move they probably should have.
IMO, they would have been best as a white label provider with good editing tools.
Granted, I'm armchair CEO postulating about it, but that always seemed like a good niche that would cover the rest of the subsets in a variety of ways, especially if they had embedded a monetization program via ads like YouTube as a sub-brand for creators. A possible 1-2 punch to sustainable revenue.