Vine never allowed more than a 6 second clip. Other platforms immediately included short video formats upon Vines success, but added more flexibility to content creators. When content creators got “Vine famous” they moved to other platforms that allowed for flexibility in content. Vine died when it had no more creators.
It is content and content creators that make a platform successful or not. It’s why platforms like Netflix, YouTube, Twitch, etc., pay big creators millions of dollars for exclusive rights to their content. Anyone can make a content sharing platform, but they can’t take content.