By normal use I'm pretty sure Monty meant under the parameters TM suggest for use.
OOf the examples you mentioned: a stock vsr's sears last ages, if upgraded then yeah they'll blow. Pistol slides? Fine on the gasses they're designed for, if you use green or whatever higher pressured gas then there'll be issues.
Can't comment on the gearsets but I'd bet the majority have had uprated springs or whatever installed, if not that then the user is likely on batteries of a higher voltage than recommended.