It's both surprising and expected that HBO fell on it's face. In the past, they blamed "demand" as being a problem which wouldn't be an issue if there service was built right https://mashable.com/2014/04/07/hbo-go-streaming-failure/

Today, they're creating a whole new set of problems https://www.cheatsheet.com/entertainment/hbo-max-is-a-failed-opportunity-with-no-buzz-according-to-analysts.html/

There are a lot of companies looking to use the streaming model for their own endeavors and though it's expensive, it's entirely doable. HBO, however, is making it a lot harder than it has to be https://www.bluelabellabs.com/blog/what-to-know-when-developing-a-streaming-app/

I'm really curious as to what they used on their backend as a company that big (and considering how well their content does) shouldn't have had any issue financing the tech that goes into capably delivering content through a single app. There's no reason, especially on the tech side, to not have a consolidated service that not only works, but doesn't confuse the shit out of users. Basically, they could be solving a couple different problems by just packing things together.