According to ---MIKE--- :

That information is bogus. Dimmer switches are solid state devices that
chop of part of the AC sine wave. I suppose they could fail but I have
one in a homemade electric blanket control that has been working for 25
years.

They most certainly can fail. Being semiconductor devices, they
can fail real fast too. An accidental short on the output side
of a dimmer that's too fast even for a breaker to notice can
fry a dimmer.

Electric blankets are nice "safe" pure resistive devices that are
relatively friendly to semiconductor dimmers. Lightbulbs are worse.
There are things that are worse still. Like motors. The motor-rated
dimmer on our ceiling fan died a few years ago (installed in 1984).

I've seen a handful of dimmers die within days of being installed,
or be dead when the circuit is first turned on. Dimmers also
occasionally die mechanically.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.