I place very strong bets that Adobe will create a dominant tool here. It will be nearly identical to flash but emit all the new fangled html5 asm.js stuff instead - in some nice tight drop-in way ... like
<div id="container">
<script src="//ad.be/UNIQID"></script>
</div>
Where ad.be is a "cloud" service you pay $xx/month to "host" your "app" for you. Essentially you make the thing, it saves to the cloud, generates your uniqid, and you put it in a container. They keep the source file and can continually regenerate the js as their "engine" improves and browser tech moves forward. It's a future-proof plugin-less flash with a large existing user and customer base.
If that's the flow, Adobe might as well just start minting money.