You are not alone. If I ran thin tires I would never need to buy tubes I find so many around here. This AM I found a tire iron next to a xtra long valve stem tube. That rider must have been in a real hurry. The tube had only one pinprick and no patches. I rarely find tubes fat enough for mu 700x38 tires. Tires like that have fewer flats and/or riders with tires like that save and patch tubes. I have never found MTB tubes that would work for the beater bikes used by day laborers and field workers. I can't guess just why.

On club rides I carry a fat spare for myself and a few skinny ones for others. After today I can carry a spare with a 2" valve stem.