> Benefit for the user, yes.
I would agree with that if everyone (companies) actually did that, but they don't. Often they pick the popular platforms, or choose frameworks that allow for a single codebase and output a often subpar UX App, or just don't make the app to begin with.
Making it harder for a company to give the end user the product, even if an arguably better product, is not always a win for the user.