Python gets forked in other investment banks as well. I wouldn’t say that is evidence of any deficiencies, rather they just want to deal with their own idiosyncrasies.
The main user has been writing extensions to the compiler that they test before pushing for integration like they have done for the past twenty years or so. They publish these versions since last year.
Hardly a failure and certainly not something mandatory to keep things from failing over. Your initial comment is extremely disingenuous.
A different perspective is that JS has made practical application of PLT part of their secret sauce, and deepening into their PLT roots is thickening the sauce.
