After that, security concerns lead to browsers eventually deprecating their plugin support. But it started with Flash getting a huge access denied on mobile, courtesy of Steve Jobs.
So, Flash became a lot less popular after that and Apple and Google successfully transitioned a lot of that stuff to their native mobile SDKs. That's why you have lots of games on IOS and Android and not a whole lot on the web these days. HTML 5 is hopelessly clumsy for that sort of thing.
A lot of the stuff people did with Flash is of course technically doable with HTML5 but mostly it seems designers shy away from doing those things because it's too hard.
Wasm is going to open up a lot of native and mobile SDKs for the web. And the web of course also works on mobile. There might even come an end to Apple blocking non-safari browsers in their app store.