Xerox tried to sue Apple but it went nowhere. Apple did improve quite a bit on the basic Xerox concept, and managed to shoehorn it into a relatively inexpensive computer. Only large corporations could afford what Xerox eventually made from the technology.
OTOH, Microsoft tried to copy Apple and produced some quite inferior copies that had problems running well on current hardware. BTW, Microsoft did use Apple code in Windows without permission. Microsoft had to pay out a lot for that.
Yeah, the entry level Xerox Star was $16,000, not exactly your average desk top computer.