Same is true of toy trains. While the Lionel brand exists (and bought American Flyer), the ownership is several layers removed from that of the 1950s. On the other hand, there are several manufacturers that are relatively new and the choices available to consumers are plentiful and reproduction parts for the vintage stuff allow us big kids to keep things running.
While many, even most of the old, classic names in audio are gone or considerably changed, it's remarkable to me that we can still keep 40 and 50 year old gear running and sounding as good as it ever did.