WebAssembly will not revolutionize anything.
It's like java where people claim it's as fast as native code, and yet every single program runs like a dog and takes 100 times the resources. Only worse because it runs in a browser.
The JVM is an extremely fast system and if you run java on top of it that is fine. There is a reason so many of the world changing distributed systems (Cassandra, Kafka, ZooKeeper, etc) are built on top of it.
I believe what you are thinking of our java business systems which are usually bloated/slow and developed by similar developers who think backends can be automated.
There is trade-offs on both cases, if you can optimize for developer speed and sacrifice app performance that might be fine for your use-case. Software applies to pretty much every industry and not everyone needs scale but not everyone can live with poor performance either.
Startup cost on server side apps is big O of 0. The average JVM for most apps run from maybe 1 hour (continuous deployment shops) to 1 month (slower to release shops). 3 seconds to start the JVM? Does't matter in either of those, don't server traffic until it is done.
You're wrong.
(See, I can just drop off one line unjustified comments too, but I wont~)
WPF native applications are failing against electron applications; slack, atom, vscode. If you think that because it runs in a browser it'll be slow, try writing a native windows 10 application sometime. You'll be both astonished and disappointed by how terribly slow the 'GPU accelerated' application is.
All web assembly does is cement this desktop dominance from 'native' applications and allow people to start pushing realistically into the mobile space with react native, etc.
You don't think it'll revolutionize anything? Haaaa~
I write Windows 10 applications for a living. I've never had any performance issue...
Dalvik's major advancement was faster class loading.