The prepping hobby and thoughtful natural disaster preparedness combined with the coalescing around just one small stove canister design seems (non-scientific assessment alert!) to have improved the availability of Lindal valve canisters. Plus, small adapters for stove-to-butane cylinders and -propane canisters are available. (Hmm. The thought of resorting to a 1 lb. propane canister while cycletouring is equal parts humorous and painful.)
I had not thought of that as a reason why the'd be more available, but I believe it may be true.
Heet also deals with water in fuel lines and is sold year-round throughout the southern US as well.
I figured they might be a little less available in the south, but indeed I can find the here in Tallahassee and didn't have trouble finding them when riding the Southern Tier.
Oh and any of the pressurized liquid fuel stoves that I have used have a bit of a drill to firing them up. Not big deal, but after not using them for a year or more I find it prudent to practice the procedure a few times at home before heading out on a trip. That seems to be true of my SVEA 123 and my Whisperlite even if I have used them hundreds of times. Canister stoves and pop can stoves are simple enough as to not require that IME.