I suspect the net result will be that more Pro $100 subscribers upgrade to $200/mo. If you explicitly do simpler stuff with Opus, you generally have enough Fable time for most programming and planning tasks.
$100 Claude and $100 ChatGPT Pro is the best value for $200/month. They can see each others' mistakes.
Not to mention a lot of people who already have more than one max20 sub getting additional ones.