Whereas you would have that in a Canvas or OpenGL equivalent web game?
>right clicking causes things to happen.
That's already the case for tons of websites, there's support for that in web standards.
>There's a reason why flash died out, and it's not only apple.
Yes. It was controlled by a single company, IDEs were paid for, it was more marketed to designer types, and it was frequently slow and used for apps and annoying stuff.