No it's also all the minor problems: lubricants don't flow the same, grease dries out on bearings, rocket launches shake the hell out of their payloads, the thermal differentials across a structure are enormous, vibration doesn't damp into the earth it just rings through the structure till it's lost as heat.

All solvable, but all difficult and unexpected problems which make everything about operating in space difficult.

And probably the biggest one: absolutely no possibility of service or cheap replacement (sure you don't repair a computer on earth, but you don't need a rocket launch to put a new rack in).