You focused on price and I think that's a significant factor. Where once Netflix was $8 not really that long ago, it's now $15.50, which is more expensive than HBO (and HBO Max with the merger has an even deeper catalog than it did in the HBO Now time, even though the HBO Now software and website was IMHO
much better).
What these media companies seem to want is for us to pay $100/month in various streaming services rather than the $80/month we were paying for cable because, hey, we should pay for the privilege of unbundling right? I refuse. Netflix is no longer an automatic renewal. I'll sign up for it 1-2 months a year to binge watch on certain shows.
But you glossed over a really important point I haven't seen given much attention: the pandemic. The pandemic was a huge boost for subscriber numbers for obvious reasons and we're now pretty much at the end of the pandemic (as far as staying indoors goes, anyway). That has to have an impact.
Additionaly, Russia's invasion of Ukraine has cut off hundreds of thousands of subscribers due to the sanctions. IIRC I heard this was 700,000. If so, isn't down 200K still a net increase?
The stock market routinely overbuys and oversells on good and bad news. It's the fear and greed cycle. And this honestly feels like an overreaction that'll be corrected as soon as Netflix spends some time controlling costs.