I was at Sun when SPARC was invented. And I think Sun killed it.

Every time someone started trying to take advantage of the "open" nature of SPARC, Sun would out compete them, fairly or not. It was a pretty open secret that Sun had hitched its wagon to the "best" processor for running Unix servers. As I told the leadership after I left that Sun was becoming DEC. They were retreating to the enterprise data center, nobody was buying workstations any more, and Solaris was not getting any more open. I suggested they build servers with the Opteron too :-).

The changing market dynamics of cloud were pretty tied to cheap 64 bit servers. Opteron forced that on everyone. Intel would have gladly dragged it on x64 and sold high margin, "not cloud friendly" Itaniums.