Yes. I wish we could use the JIT – it would make computational heavy stuff way faster. Most games however aren't performance bound by computation, but by drawing. Not having the JIT isn't as bad as it may seem.

Also, JavaScriptCore recently features a new "low level interpreter" – still not as fast as the JIT, but way faster than it was a few month ago: http://wingolog.org/archives/2012/06/27/inside-javascriptcor...