Honestly Prime is the only thing I stay signed up to and thats mostly for the delivery, the streaming coming to a few pounds a month is tolerable.
I think when the noose really starts to tightened though will be when they lock you down to long contracts, at the moment long contracts are cheaper but I would not eb shocked to see Netflix, Disney+ extra lock people down to 6 months or 12 months in the not too distant future. Stop people signing up for shorter lenghts of time to watch a few things and then leave.