Speaking at least for my area (Detroit television market), a lot of local channels use their digital allotment to run a "Whatever I Can Syndicate For The Cheape

Speaking at least for my area (Detroit television market), a lot of local channels use their digital allotment to run a "Whatever I Can Syndicate For The Cheapest" channel at SD quality. It looks a lot like the UHF syndicated content when I was a kid. I wouldn't be surprised All in the Family shows up there, a lot of contemporaneous stuff does. Not that you're wrong about Seinfeld being, oh, let me guess, somewhere between two to six orders of magnitude more popular, depending on how many dozens of people are watching the "Cheap Syndication" subchannel at any given time.