that's all true, but I believe that's just another byproduct of the age of online/delivery commerce. As I recall life before Al Gore invented the internet & put us on this trajectory, I never had a problem going to the store whether it was Sears, the mall, or the mom & pop shop & grabbing whatever I needed, things use to be in stock when it made sense for brick & mortar to stock everything as they were the only game in town...
If, and it's a big if, retail stores ever make a comeback it follows that the out-of-stock problem will also largely disappear.
Unfortunately, I can't say I had the same experience. It may have just been the particular town in question: Salinas, California. I was heard to say MANY times "Typical Salinas business: 'Temporarily out of stock.'". Especially at Sears. It got real old real fast.
I'm just thankful we have a local hardware store that has been in the same location since 1880 - if its oddball, they have it. If its more "commercial/industrial", they have it. Fantastic place to shop - but don't even TRY to find "it" - ask one of the guys hanging out by the register, and they'll lead you right to "it" - its a multi story warren spread through 3 buildings.
There is an old time auto parts store near where I lived in California - has been there since just after the war. Same drill, they probably have "it" in stock when nobody else does. If they don't have it in stock, they can get it in next day - even stuff that the other guys can't order and you play hell finding it online. I haven't found one like it here in Florida.