Why don't car companies reproduce old models?

Why doesn't ford sell old mustangs or Jaguar sell new E-types with new suspension and engine etc. I think car companies would make a killing remaking replicas with new guts and if

I've thought that, too. They sort of do this: the new Mustang is meant to resemble the old Shelby. Mazda Miata was meant to resemble an Austin Healey. And of course Volkwagon reissued the Bug. But I agree with you: I'd love to have 2014 Mustage be a complete ringer for the '66 but with new guts.