instructions unclear, set fire to my entire DVD collection

Or save them redundantly to several archive-quality hdds. Why have 20 blu-ray dvds for one copy of a collection when you could have 3 complete copies on 3 hdd. Both are life limited media, both will eventually require re-archiving. One has potential for mechanical failure, the other more likely to physically degrade. Pick your poison, or do one of each.

Genuinely curious how are publishers limiting physical media? I haven't bought a blu-ray in a long while.

"The powers that be" aren't doing some kind of nefarious thing here. Physical media is only worth producing if they're doing it at incredibly high volumes. The smaller the run, the more expensive it is for each individual unit. Fewer and fewer people are buying, and there are fewer and fewer physical devices out there capable of playing the media.

For them, it's a simple calculation of the cost of producing physical media, getting it from the factory to stores, paying the stores to shelve it, etc. vs. simply having a website with media files on it.

While there are some people who still prefer physical media, for the most part consumers also prefer just going to a website and clicking a button vs. driving to a store, parking, searching the shelves in the hope they have what they're looking for, and so-on. In addition, as fewer companies put out physical media, it's harder to find the physical media you want in the stores, so more people prefer to go online, which leads to less demand for physical media, fewer choices on the shelves, and more demand for streaming.

I'm sure the bonus of consumers rarely having a way to view a movie or listen to a song an unlimited number of times without paying is something the media companies also enjoy. But, the main reason physical media is disappearing isn't some kind of conspiracy by the mysterious "powers that be", it's a simple profit calculation by accountants at Sony and Disney.