$ uptime 12:34pm up 1221 day(s), 20:44, 1 user, load average: 0.00, 0.02, 0.02 $
Granted, the above is an internal webserver without a hell of a lot of load on it, but 1221 days is good in anyone's book.
I can understand making Solaris available on Intel hardware, as it allows folks who work with Sun hardware to have an inexpensive way to have Solaris available on a workstation without the expense of a full-blown Sun Server.
Why would anyone run Linux on production Sun hardware?
Some people hate anything other than Linux. They are quite fanatical about it, and are typically referred to as "zealots". They put Sun down at every opportunity, ignore all of Sun's contributions to open source as hypocritical, even accuse them of attacking Linux along with SCO and Microsoft. Surely you've seen them, impossible to miss these days.