There are a lot of reasons. One is that the streaming services are all competing for the same user base, so there's a race to the bottom on price. For instance. I have HBO Max, and Paramount +, and pay for neither because they were free with other things I was getting. These subscriptions aren't going to generate much revenue. When it was "You need one, maybe two streaming services and you can ditch cable/satellite" that was a compelling fiscal argument for consumers. Now, if you're going to get all the content you want you will probably need 4/5/6 streaming services, each with it's own monthly fee, and it's suddenly just as expensive (or more so) than Cable/Satellite.
The streaming services all thought it they just had a couple really "must have" bits of content (like Paramount+ having the Star Trek IP) people would pay for an independent streaming service for it. They seem to be really wrong on this one. This is why they all took their content off Hulu and Netflix and insisted on starting their own services. They're learning now that was a greedy and bad move. The closest to pulling this off was Disney just because of the sheer volume of kids-centric content (Plus Marvel, and Star Wars...) they own and even they're struggling mightily.