I don't know of anything major, but Pennsylvania's liquor stores (wine and hard stuff) were and remain the sole source of that for within Pennsylvania.
At the end of WW II the govt had a monopoly on reactor by-products used for medical and physics research.
Yes and no. While Sears had a big array of products, it didn't sell everything and there were other retail stores that did. (Did Sears have book departments? Grocery stores?) Further, Sears was a "full service" store, but there were other high-end and low-end stores (esp low-end discounters). Sears may have been the _biggest_, but it certainly had plenty of competition in retail.
Again, yes and no. I don't like buying clothing via the Internet because size labels have terribly high variances (I have "large" items that are too tight on me and "medium" items that swim on me. You have to try something on every time regardless of the stated "size".)
I don't like the discount/specialty stores since they don't offer the service/support/guarantee/integrity that the traditional stores do. For instance, at "Best Buy" I bought software that came with a rebate. It turned out I could've bought the same product at another store. The other store had a cheaper price (no rebate). They never sent me the rebate check (for $20) so I grossly overpaid. The big dept stores will cheerfully take stuff back, the discounters don't like it even if it's obviously defective merchandise. Further, the discounters are fast and free on product spec labels, I remember them pushing TVs supposedly having stereo but were actually mono.
Lastly, on sale items, the dept store prices are competitive.
Some specialty/discount stores have a relatively short life.
As I said, the railroads were FORBIDDEN by the govt to do what you suggest, and ORDERED to divest what things they had done. For example, the railroads set up bus lines to more efficiently serve light-volume areas, but the govt ordered them out. Railroads were regulated, just like the phone company, and the phone company was tightly limited into what communication product markets it could enter. (Western Electric had sound systems they had to discontinue.)
Now Hollywood was late in shifting its resources to television, initially it hated TV thinking of it as an enemy.
Further, IBM was exactly as you describe, seeing punch cards as its business, not electronic computers, and had to rush to catch up when they finally realized they missed the first boat. Fortunately, they were doing some experiments and research, Watson Sr was not as anti-electronics as claimed and he initiated basic research during the war.
The thing is, I'm far from convinced those other stores are truly superior. They actually seem to have a smaller selection and not the most desirable models. I recall shopping for a VCR and a TV (a few years ago) at both types I ended up getting the best price and selection from a traditional dept store, not the discounters or specialty. I checked the mfr's web site and only the dept stores had the most desirable model I wanted.
I would be curious: take men's dress suits. What is the breakdown for men buying suits? I dobut Walmart/Kmart are that big. One discounter, Today's Man, went out of business.
I used to listen to it at night in Phila.[TELECOM Digest Editor's Note: WLS comes booming in at night here in Independence, also. PAT]