Languages like Smalltalk or Lisp can have it both ways, the problem with Ruby is the manpower to have a comparable JIT available, although MJIT isn't the only one already available.
...Cincom is the largest commercial provider of Smalltalk in the world, with twice as many partners and customers than all other commercial providers combined."
You seem to be suggesting that Smalltalk implementations are a whole lot faster than current Ruby ?
They are a whole lot faster than Matz's 2008 Ruby 1.8.7 but so is current Ruby:
https://benchmarksgame-team.pages.debian.net/benchmarksgame/...