Thorn-resistant inner tubes have much, much thicker rubber and I only have to top up every 6-8 wks with daily riding.

Still, I'm with the OP on this, why are tires/tubes the most unreliable part of the modern bike? (Yes, I know Conti Gatorskins, Specialized Armadillos, and Schwalbe Marathons exist . . . ) The fact is, tube technology sucks, just one example is the incidence of cut valves. Specifically, Bontrager has for several years been selling Presta valve tires that have inherently defective valves which separate from the rubber after a few weeks of riding. You guys who fetish-ize changing tires and and pumping tubes -- and thus showing your devotion to the sport -- probably don't give a dang.