Given that Ford makes the Escort, why do we need Kia or Lexus or Hummer?
I've often wondered about that, especially Kia and Lexus
Manufacturers make JVMs optimised for their specific needs and desires. Someone might want one that has a smaller memory footprint and doesn't need some things the default one has. Another might want more security as standard and is willing to sacrifice performance for that. Etc. etc.