I really don't intend to defend BMW in any way, as I greatly miss the days of newtis.com and would really, really like it if the parts catalog information at realoem.com went past 2019, but here's some first hand, anecdotal information I can pass on in my particular case. This is an interesting discussion though.
I have one recent new purchase BMW, a 2021 X3e PHEV and a sort of BMW, a 2022 Toyota Supra.
For the X3e, for $30/24 hr purchase, I could download all of the training/familiarization material (OK, I'm kind of a geek that way) and pull copies of maintenance procedures and repair instructions for about anything I could think of at the time. There is definitely a learning curve, but one of the nice thing about all the maintenance procedures (engine oil and filter, brake pads, most other consumables, etc) is that there's way to pull down a view that has all of the instructions, including access, torques, etc. Whether or not this is technically within the license agreement I clicked through, copies of these are now something I have locally saved-- it definitely would be a license violation to share the information with others without permission to do so. While I'd like to have paid less, I'm happy to have been able to get the information in a one stop manner, though integration with parts catalog information wasn't great, but that may be a learning curve issue on my part. I did all this either last fall or this spring.
Theoretically, it looks like I could download the proprietary diagnostic software and use it as well, but the likelihood of me getting all that up and running (and getting the necessary cables) short of buying at least a monthly subscription is pretty unlikely , but again, some portion of that may be learning curve/personal issue. And I also think it would only be functional during the subscription period.
I can also say that expanded/completed procedure view seems to be something BMW had only partially introduced on the 2015 i8 I used to own, so it feels kind of new to me-- or it's quite possible the i8 is just unusual that way. That kind of capability definitely was not there in the bootleg TIS information I used on when I had a 2007 Z4 Coupe and 2008 328xi.
Moving on to the Supra-- well, to start with, access to the repair instructions is cheaper at $20 for a 48 hour period. There's an entirely different learning curve, and the equivalent training/familiarization material appears to be spread across multiple documents/downloads, and I could find no equivalent expanded procedure view that pulled in all of the repair instructions and technical information for a given procedure-- had to drill down through hyperlinks into multiple other documents. Again, I may not have made my way through the learning curve, but the information was much harder to collect and reference. Parts catalog information wasn't any easier to access. As a point of information, it looks like Snap-On may have actually taken my money for this after accessing this through the mytoyota web site.
So, I pulled the VIN for a BMW Z4 of the most corresponding model off of a dealer's website, paid my $30 to BMW, where I had access to all the same repair information, but it was better organized and easier to reference. Could also pull the training/familiarization for the Z4 and even some 5 and 7 series docs referenced by those. Realize the Supra/Z4 is a special case, but I definitely got better value for my money out of BMW.
And as a point of information, for my wife's 2012 Tahoe, the rear gate exterior window switch was broken. Wildly varying repair information was available through YouTube and forums, with it all on me to figure out which may have been the best. I didn't consider looking at what a blind AllData DIY purchase would have run me at the time, but looking now, it would be $19.99 for 30 days, but for a single vehicle. I just decided to have the shop down the road from me do the job.
I'd have to characterize the costs in all these cases as reasonable, however, there is a real problem in that in each case you're making a Forrest Gump box of chocolates purchase.
Laying out the support schemes for a DIYer could be a very interesting editorial project for the magazine, but I suspect that it wouldn't stay current for very long. If an article included information from the OEMs and what their current outlook/policies are, that would also be interesting.