I think it's fair to have a paid subscription if you're using Sony's servers. I thought you would be able to stream from your own PS5 across the internet (like with Steam).
Despite the technical limitations, the PlayStation Portal has proved successful since its launch, with US sales estimated to be between 420,000 and 630,000 units, exceeding Sony's initial expectations.
I wonder what their sales estimates were, I would have thought their unit sales targets would be higher.