The metal stems come on the rims from Dinan, and the tires have been replaced several times without any issues.
I can see your reasoning, texcept that the shop didn't even have the right size when it first happened, and claimed they couldn't get valve stems that would fit. when I had it towed there this time, they discovered they could order them overnight.
When I tried Summit earlier, the ones I needed were OOS.
And the failure happened because they didn't notice that the locknut was missing from the valve stem, so the nut holding the stem in spun loose. It came off in my hand when I tried adding air by the side of the road. I'd call it sloppy work really.