Did you ever consider that some people live in areas where they can only get spotty Internet and/or they can't afford a bunch of streaming services?
Sure, but you seemed to say you simply prefer to own physical media. Which, I can say, most of us do. Your position seem to indicate you'd prefer a doc to either go straight to physical media release, or I suppose be released day-and-date on disc and streaming. I and a few others have pointed out that that idea ignores how streaming services work (the point is to have exclusive content, at least during a certain window, to entice people to join the service), and ignores that getting a streamer on board is the *best* way to procure a good budget for a documentary and get *far wider* distribution for people to see it.
The point would be to have a documentary that's something more like "The Beatles Anthology" and not so much like Billy Hinsche's home-made straight-to-DVD documentaries (which are just fine; I'm just using that as an example of a project made with essentially next to zero budget and few resources).
If someone says "Man, I wish I could watch this on a streamer, but my area doesn't have fast enough internet", I of course would not then continue to advise them to try it. Stuff can be streamed in SD at a pretty low bitrate via most streaming services, so unless an area has no option but dial-up, I'm not sure it would be difficult to stream video even with lower speed old DSL, or what have you. But sure, I'm aware there are rural areas where streaming can't be done (or done easily or cheaply, meaning without a satellite internet set up, etc.).
As for cost, as several folks have been saying, many of the streaming services have free trials.
And, the monthly cost of even the most expensive large streaming service is still cheaper than a DVD or Blu-ray set would be of a BB documentary.
Watching a BB doc on a streaming services wouldn't require "a bunch" of subscriptions. It would only take one, and I'd guess it would probably only require one month or maybe even a single day to watch it all, depending on the length of the doc and whether, if it's in multiple parts, the service drops all episodes at once or releases them weekly.