That's not the case. Their business model of having a selection of electronic parts in every store was flawed. Perhaps it was good enough for 1960's when a ham was expected to wind his own inductors and make his own high voltage capacitors. Even making of a power transformer was NOT out of the question, and I had some quantity of magnetics to do so. You could build a radio with parts selected from a list that does not exceed a few hundred items.
However today this is utterly not the case. There are tens of millions of different electronic components today, and you want to have access to all of them because you never know what this or that design calls for. Digi-Key offers mail order of nearly anything you may desire, and their prices are pretty low for a retail facility. (You can do better by going with Avnet and their ilk, but they require volume buy.)
What I'm saying is that RS could not stock enough parts in their retail outlets. It would be outrageously expensive, and they'd never be able to keep track of those parts. (Some of them are invisible without a microscope.) Digi-Key has a single, highly automated warehouse that ships orders within an hour or two from the moment you click "Submit order." You can order by 5PM and receive the shipment by 9am next morning. Or you can select USPS shipping and receive a small box a few days later for a song ($3 or so.) But the real advantage of distributors like Digi-Key, Mouser, Allied, and a few more is that they have a lot of stuff. No single brick-and-mortar store can stock even 1% of what they have. This means that Radio Shack just reached the end of that particular road. They had to change... but they had neither skills to do so, nor wisdom to understand that.
Just about everyone today one can find a flea market..and depending on the size, there's usually one or more vendors carrying the same stuff that RS stocks nowadays, but a lot cheaper..and that person is actually willing to talk to you, and knows his stuff.
Personal reflection. In the early 60's when I was a young teen... RS was in its heyday, I bought a Heathkit tuner and amp..the store manager..and back then they were long time employees..they were paid based on how well the store did..they were almost like owner-operators...before I built them..he had me come back a few times for soldering lessons..needless to say, they came out working superbly..had them for years..