As far as I'm aware on this matter, privacy beginners wouldn't know what they would want to protect themselves from at first. They have tons of options, and the analysis paralysis would come into play. I was somewaht like that when I was starting my Linux journey in 2020, though I had some inkling of it since 2018 (I just had no idea as of yet).
The biggest problem I see with threat planning is exactly whom one would want to protect themselves against, be it Big Tech, corporations, governments, etc. That said, I think threat models are good for those who are starting to understand how to not overshare everything if their lives are in danger. Otherwise, I don't really see a point into it as of right now (I would, however, take a look at options beforehand so I don't goof something up and overshare again).
While I get that we do want a grounded floor to fall back to in a sense, I think there is really only one that could be the most viable, and the reason all the other threats exist: religious organizations. I always harp on one of them and for good reason. I won't go into it here, as I did so otherwise. All I will say about it is that there is a lot of threat modelling to be done with looking at this light.
I'd rather leave threat modelling to the pros if I'm being honest here, though I only have that one I described (there are several highly personal reasons I won't go into here on that matter). Despite that, however, I'd be remiss to not entirely be unopposed to threat modelling if needed for certain purposes.
That's how I attempt to see it from both sides of the argument.