that's not really true. i've superheated tap water at least a dozen times. never had a negative consequence from it, besides having to clean up some water, so it's also not something that really bothers me. from my experience the superheated state can be surprisingly stable, a couple times only explosively boiling over while being poured, instead of the moment I grab the container.

edit: as far as 'nobody' using Pyrex, my preferred container for heating water is a big Pyrex measuring cup.