Hardware synths can crash, just like a computer can crash. The fun thing is that the hardware generally crashes when a specific set of conditions are matched. It's reproducible. Software can crash if a specific set of conditions are met or ... if you've got bad karma or something.
Easiest way to crash a piece of hardware: pull the plug.
I've never played a synth where it boots up instantly. It generally has to do some checks and then it comes on. Hey, if it's analog synth, it might take a bit to warm up, too.
Most hardware synths have at least one moving part: a cooling fan. You've also got buttons and stuff -- and membrane keys are annoying to replace. Even if you've got only one sound, you've got an on and off switch. And, of course, if you've got a keyboard, you've got, well, keys.
"Solid state" is a term to describe something that can function without any moving parts. A solid state (hard) drive (SSD) is the most prevalent example of this at this time. However, they can overheat and their firmware can be glitchy -- including ceasing to function if you upgrade the firmware wrong or the operating system on your computer.
Of course, you've also gotta have an amplifier of some sort ....
As one final example, the Apple "chicklet-style" keyboard (which I like very much) has firmware to make it work. There have been a couple viruses that can infect the firmware. Kewl, no?
(Sorry, dude. I'm a computer tech. I deal with this type of stuff all the time )