Is it that the decade of 0% interest rates and angel funding for startups lulled us into unrealistically thinking we could get unlimited everything for 9.99 per month, or is it that companies are suddenly starting to rip off people?
As an end consumer it's impossible to gauge what is a proper price for entertainment.
As with many things, it really is likely a mixture of both. Very possible that 9.99 was unrealistically low, but the current streaming market and "inflation" smoke screening is also enabling some real squeezing of consumers.
It was maybe too low for their awesome library they had at the start (though their initial pricing was still more than a lot of their customers spent in a year for movies/TV prior).
It's criminally overpriced for their awful library now.