In my experiences over the decades, I have had some of both, SS and tube equipment fail. Most have been reliable. I had an instance or two of bad design that eventually led to failure, and bad parts or assembly.
Some manufacturers are known for reliability and great sound. I won’t buy from a certain manufacturer that has good sound, but has proven unreliable and problematic..
Tube amps can be very reliable as much of the hardworking parts are the tubes themselves. SS has come a long way and I don’t have to have tubes anymore ..