So does that mean eventually the bulb will just shatter? Or die out?
That is something I can not say for sure. Depending on the quality of the glass used for that bulb batch, it could work it's full life fine. It could also physically fail or just burn out more rapidly.
I have replaced industrial halogen outdoor flood lights where I forgot to wipe my finger prints off and every once in awhile one explodes when it turns on from the heat and finger oil on the glass. Other times no problems. It all depends on that particular bulb.
I am sure you have seen a normal light bulb get broke when it was on. You see a little puff of flame and smoke and that is it. That is a lot larger with a HID bulb.
I'm not trying to scare you, but that is a variable that could cause you to have glass blown all over your plants and at worse a fire.
Fire is a big concern in this hobby and you want to go out of your way to avoid adding in more variables that could bite you in the ass.
A $100 bulb means nothing to me compared to my families safety and home security. For me, not worth the risk if the bulb is not contained in a glass bottom type of hood.