You’re conflating two things.
HBO and WB studios are two separate things.
HBO being niche is fine. It only programs for two nights a week with an emphasis on premium event tv on Sunday(Soprano, SATC, GOT, Succession). It reruns the other nights. WB makes movies and tv shows for cable, network, and now streaming.
HBOMax is a platform fed from these two entities. It can’t be niche. It has to cater to a worldwide audience 365 for 24 hrs a day.
Now that other studios are keeping their IPs exclusive to their own platforms, you might not see TOP Gun Maverick on HBO cause Paramount wants to to sign up for their service. Marvel stays on Disney+, etc.
So if people are tightening their belts for one or two streamers… being the home of 20 seasons of past My 600 pound Life ain’t going to make people jump on your service as opposed to getting scripted cartoons for their kids to watch, new scripted movies not on DVD, and watercooler shows to talk about on Reddit like Westworld.