DEC?
Erm I think you will find DEC predates PARC by a decade or so and was a spinoff from an MIT research lab on the other side of the continent.
Having said that I think the "XEROX invented it than didnt sell it" story is overdone. This industry does not reward pioneers and innovators. Osbourne created the first portable, VIsicalc the first spreadsheet, Ingress the first commercial RDBMS, CPM the first PC OS, ATARI the first dedicated games machine, Wang the first word processor , DEC the first search engine etc, etc, These innovators are all now defunct in spite of creating billion dollar markets which are domiated by MS, Sony and Oracle etc.
I acttually worked with a "Xerox PC" and very nice it was too, the word processor is still one of the best I have ever come across. However they were locked into a "multiple micro" 8 bit 8080 processor archictecture. They overcame the contemporary hardware limitations by designing an OS which used multple processors and mutilple address "segments" to overcome the 64K address space limitations. This approach lost viability when the 386 processor was released - It was simply too much work to re-write the OS for a single 16 bit processor.