Movie theater butter has absolutely won over real butter in its niche. Pam and its contemporaries are also wildly popular over butter for pan cooking.
All things considered fake butter has got to be one of the most successful vegan alternatives since non-vegans will choose it over butter.
I mean biotech technologies that are essentially artificial milk glands, producing something very close to 'real' milk, without cows.
Why grow a whole cow when we just want what the milk glands secrete, why grow a whole tree when we just want orange juice? Etc.
I don't prefer it over butter although this is largely a matter of taste, but more importantly IMO, even if it was touted as a healthy alternative to butter in the 70s-80s, today margarine has been shown not to really be better after all. It's not used much anymore by people less than 50 or so, in France.
I think modern margarine is probably better as it doesn't contain much transfats anymore, but in France the damage to its reputation has been done already.
I live in Belgium though and people still use margarine here, but as far as I can't tell it's mostly because they just call everything "butter" and don't know the difference between margarine or butter.
https://www.jeffnobbs.com/posts/death-by-vegetable-oil-what-...