Best to minimize anecdote and speculation on what is wrong. We don't know why these particular amps failed, we do know that discrete amplifiers are
not intrinsically more reliable than chip-based amps.
In fact, modern chip amps have advanced reliability and safety features built in (temperature and voltage protection, short-circuit protection, soft-start and -stop, clipping, etc.) Discrete require all of this to be designed, built, and tested by the product development team. Also, IC manufacturers offer this in a package that is rel-tested. So long as the product doesn't do anything
odd in implementation, or mess up during manufacturing and testing, the IC isn't intrinsically disadvantage to fail. The presence or absence of luxury components, like switches from certain regions, or inductors wound by certain individuals

, doesn't fundamentally change the product's reliability.
Serviceability is
sometimes better for discrete circuit implementations.