[hamei]

I'm unsure why SGI granite Trinitrons were [fixed frequency], I assume cost and availably at that size of CRT made that decision (It was a poor one, but did lock people into specific monitors...which did make SGI money in the short term). 

They weren't. Early ones were but by the time of the nice ones - Octane-ish ? 1995 or so ? those were multi-synch. The ones with flatter screens and the 24" one, multi-sync. I think all Sonys ? Have seen the same monitors as IBM, Sun, and SGI.

Early big monitors were fixed because they came with a workstation, not a peecee.  As such they were not expected to get hooked up to various different computers, it was "this setup goes on your desk" as a package. And you paid big for anything over 13". In fact 13" color wasn't cheap.

At the beginning of desktops people either soldered up their own mainboards and peripherals or bought the setup complete, not so much in the middle mix-and-match.