I've seen a lot of people mentioning the lack of Roku support. I have no idea how HBO hasn't developed an app for it yet; it seems like an easy market to support. But like you mentioned, Firesticks and Chromecasts are stupid cheap. It sucks having to get a new device for a single app, but it's either that or don't use the service I guess.
There are thousands of Roku apps; creating one is not a high-tech challenge. This is just HBO [edit, thanks sibling comment by 'whatok [0]:] refusing to pay Roku's toll.
Not having a roku app is a deliberate choice. It's not like this is some engineering failure. Hbo and roku got in some sort of fight, I assume hbo wants to be paid by roku.
it doesn’t have anything to do with developing an app and everything to do with HBO insisting on how their content is distributed. they recently reached a deal with amazon and i believe part of the deal was pulling the legacy HBO Now app and only allowing HBO Max. they want Max to be the front facing brand