My prediction is that this becomes permanent. There is no good reason to be much more expensive than opus. At $4/$20 they are roughly at parity.
Making 2/10 permanent would be a killer move and make a strong argument against open-weight. For the sake of the open weight ecosystem I hope they do not.
Isn't it essentially permanent since a new model will be out by then?
I'm guessing they do this to help move people off old models they want to depreciate. It's not a price hike for old models, it's them removing a discount!