The Root of All Evil?  Probably, though perhaps only a symptom.  When Toll Brothers and all the other production builders standardize on 20×20′ (or smaller, code minimum is 18×19′) garages without room to hang a rake or locate your 2 Waste Management bins or store your Christmas ornaments, you either hire a dumpster and downsize your crap once and for all or rent a storage unit where your crap can reside for all time raking up monthly fees that exceed the $/SF of most apartments.

Reno/Sparks/Washoe will add something like 3000 new housing units this year including apartments, and over 10,000 mini storage units.  Mini Storage used to be land use that happened in the wastelands on the far outskirts of town.  Now it is viable even at Park Lane.