Uh? Being a 'technical marvel' has little relationship with making money and without money developers may choose to do something else whenever they want..
IIRC there's a comment from Mike Pall (maybe it was here, can't bother to search it for now) where he stated very clearly that there was always enough money on the luajit table. So no financial reasons, he just wanted to do something else (and he didn't like the new lua features so much, pain to implement and all that stuff, so maybe that's the real reason...).
Features in PUC-Rio Lua after Lua 5.2 or so are mostly all terrible, with the possible exception of <toclose> (a bad version of golang's defer). So I respect the choice not to add those features. There was still lots of work to do to improve the GC and such though.
What about integers and bitops in 5.3? That seems like a big deal
Bitops are in LuaJit
Lua 5.3 integers are 64 bits long by default, and that makes a real difference.
That's trivial to implement as a C function though, so no real need to add it as a language feature