Yes, the system isn't perfectly deterministic, but on average and over a long-enough time period, it pretty much is. People are going to act irrationally, but generally people will be irrational roughly equally on either side of "rational."

In this case, the market is probably big enough that if a big retailer doesn't stock something, it's because the average person has decided that buying it elsewhere (i.e. Amazon) or not buying it at all (i.e. longer is fine) is preferable to buying it at the local store. It's not the local retailer's fault that it's unprofitable to stock that item, it's a mix of consumers and online competition making that product unprofitable to stock.

That said, you'll probably have a better shot if you go to specialized stores. In this case, look at farming and plumbing supply stores, since they're more likely to service those customers who really need that short hose today to complete a project. Your regular home improvement stores (e.g. Lowe's and Home Depot) cater to homeowners more than contractors (so having a little of everything is better than lots of something), whereas the specialist stores cater to contractors and small business owners.

I don't know what any of these words mean.