HBO has stated directly that they would lose money if they offered a la carte access to their content. Recurring revenue is an extremely powerful thing; if you have a business model that works that drives recurring revenue, you stick with it.
HBO's business model works extraordinarily well; they have almost 30 million subscribers.
I completely accept that they wouldn't be persuaded by mine either if that helps. I firmly believe however that someone will adopt this sort of model and then we'll have an empirical example to talk about.
HBO is itself effectively just a middleman (at least for most of the content we care about). Maybe we should stop talking about what HBO should do, and start talking about what companies like Blown Deadline (David Simon's production company) should do. Again, my sense is that many more potential viable productions exist than are greenlit by AMC, FX, HBO, and Showtime.
"The issue is that it would be financially irrational of them to do so, because their subscribers would defect to the online offering; they would, in effect, be offering a fire-sale on their most valuable offering."
There are three claims embedded in this argument let's break them apart individually.
1] "Users of HBO only subscribe to HBO for the original content."
Let's stipulate that this is a rational market. You've got people who pay for "all" of HBO (which spends most of its air-time showing 'movies' not original content), people who pay for it only for the original content. What is that ratio?
I'll claim that most (aka more than 51% :-) of their subscribers are movie watchers. On Comcast they have 8 channels, HBO, HBO2, HBO Family, HBO Comedy, HBO Signature, HBO Latino, HBO West, and HBO Zone. The bulk of the content is movies. Based on the value proposition "you have to pay for 8 channels at an additional $10/month ($120/year) to get your one original content show." And the fact that boxed sets of the previous year's episodes are offered for $40 - $60. I claim that the majority of HBO's paid subscription is there for the movies, and that they get HBO created content is a 'nice to have' feature.
2] "The number of people who don't subscribe to HBO because they are only interested in one show or perhaps a small number of original shows is quite small."
I don't know that number of course. But one could reason about it if you knew the resale rate of the boxed sets of original content. That is an imperfect indicator since you don't have survey data that says "are you a subscriber to HBO or not?" and you don't know which of their original content shows would continue to hold value past their air date (dramas sure, newsy stuff not so much). If someone knows what the sales rank of those boxed sets are though could get an indication. They are quite popular on bittorrent so clearly there is a demand (I know that isn't really in question)
3] "The original content is the 'most valuable offering' and the revenue generated for that net original content in a two tier model would be significantly less (fire-sale) than their current revenue."
My claim is that the number of people who subscribe to HBO just for the original content is quite low (its not a good value) thus offering the original content through another channel would not change the value proposition to a material number of current subscribers.
But capturing the revenue from people who would subscribe to a service that offered the original content would increase their bottom line.
I am really surprised they haven't A/B tested this much. Put an original series out there and offer it through a third party service as well using a modified release-window model (say a week).