Cable is a pipe to get content from TV and Film companies into the home. Netflix was also a pipe to get content from TV and Film companies into the home. The cost of TV and Film isn't magically cheaper on cable or Netflix. TV and Film companies want to get paid, and that cost gets passed on in the subscription cost. Instead of cable being a one stop shop for bundles and packages of everything, you now have to basically have multiple streaming subs that likely add up to the cost of cable.
It's the reality of the economics of TV. "TV" is "TV" regardless of whether you get it from streaming or cable. And that means the consumer cost is largely going to be the same. Back when everyone had cable, streaming was probably cheap for 2 reasons:
Subscriber acquisition practices to grow the streaming subscriber base kept cost down even if margins were low.
Streaming was the icing on the cake. So TV companies were happy to make content cheap for streaming when Cable was the main cash cow.