Watch TV from the 90s and earlier

I'm surprised there aren't more full tapings of 90's television available, as in entire blocks of broadcasting with all the commercials intact. That was how most recording would have happened, and with the start of TV Land the networks should have been able to predict there'd be a market for it in 30 years.

Storage was a problem back then.

Not really. Hoarders were already mass recording TV from home, see https://en.wikipedia.org/wiki/Marion_Stokes

Recording ~5 hours of television a night would have been a trivial cost for a network like NBC. Particularly compared to the licensing fees those hours would have had.

Which 5 hours? The programming transmitted by the network with few to no commercials, or the programming broadcast by hundreds of NBC affiliates, each with its own set of commercials paid for by local advertisers?

The storage costs wouldn't be a huge deal to either group.

In general, the affiliate nature would add a wrinkle to the whole thing, but not an insurmountable one. If nothing else, they could have used the broadcast from the affiliates they owned.

Where’s the profit motive?