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.