As far as WASM is concerned I'm more excited about the possibility to run any programming language on the web than the raw performance gains. So far it is still year(s) away from this goal(i.e. lack of web APIs/DOM access makes it useless for web dev).
In a sense, you pay those hours that you saved up by using an easier, more intuitive language like JS. Or you can choose not to and still have pretty good performance and blazing fast dev cycles.
As far as the performance is concerned I believe profilling the internals of the VM(as the author does) is not a good fix on the long term.
It's the same argument any junior engineer makes when they start at a company with a legacy codebase. They always want to start from scratch but don't realise the cost or the fact that while they'll avoid 100 mistakes of the past, they'll also make 100 new ones. Why not just make JS better? It's already happening year by year.
If we could have been able to challenge it by allowing another language in there I would like to think we wouldn't be facing a lot of the issues we do now.
The extent to which WASM could be used in the Node ecosystem would essentially be an indictment of how badly the Node community has bungled FFI. (node-ffi[0] should absolutely be added to Node core, not be independently maintained and always trailing compatibility with newer node releases, right now you have to choose between security or compatibility)
"WASM will eventually allow the same choice in the browser."
When will that actually be? That's the big question.
I wish that was the case. Yes, I know it is only receiving security updates -- but it will supposedly get those until Windows 10 is no longer supported (if I'm reading things right).
Unfortunately, that doesn't stop a bunch of people from using it. It still has a considerable amount more marketshare than Edge does (if netmarketshare.com is to be believed).