If you can be assured the tube is 100% air tight I can't see how they would dry out. On the other hand, I don't think they would age very well. Don't cigars need to breath a little when they are aging?
I occasionally enjoy a Cuesta Rey Cortez Centro Fino Sungrown, of which comes in a glass tuve. I actually take them out of the tube when I get them, and have had no problems. I actually think they turn out better with some rest in the humi, with out the tube