I think IBM buying redhat and aggressively pushing Linux was also a big factor in killing sun
[1] https://www.ibm.com/ibm/history/ibm100/us/en/icons/linux/
IBM to spend $1 billion on Linux in 2001
This long before IBM bought Red Hat in 2019
I know people at Sun who were quite chagrined about that at the time.
I think IBM buying redhat and aggressively pushing Linux was also a big factor in killing sun