In 1989, the costs appear to have been significantly different, although on a casual search I don't see list prices for eg then-older Sun models like the 3/60. A brand new Sparcstation 1 (also 1989) was far more expensive than an NCD 16 or NCD 19, and a diskless Unix workstation would need more server support and disk space than an X terminal. Today is a different thing, but that's because PC prices have dropped so dramatically.