Solid state lasers have their own complications, and generally have a much shorter wavelength (600nm to 2000 nm versus 10,600 nm for CO2) that interacts with materials very differently. There are shorter wavelength SS lasers, but their output power is relatively low. And I don’t know of any SS devices that operate in the same wavelength range as CO2 lasers.
Trying to operate SS lasers continuously (for cuts) requires a LOT of cooling. Operating them in pulsed mode works well (and can get higher peak power) with more reasonable cooling, but gives you a ragged cut, and frequently doesn’t match the same peak power from pulse to pulse.
Repair/replacement is more complicated in solid state because there are more active parts (pump, crystal, external resonator cavity, coolant jacket, etc.). For this reason, many are sold and replaced as whole units, and are quite expensive.
See also: http://www.troteclaser.com/en-US/Support/FAQs/Pages/Laser-Types.aspx