They might make less money with one super subscription than two separate ones.
I can imagine an internal analysis that says:
Move show X, Y, and Z from Netflix to HBO Max because those profiles are likely to add the second subscription.
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Piracy seems like the only thing that keeps prices/practices in check.
Yeah, I can easily see something like 2 separate at $20/month vs 1 super at $35/month (make-believe figures).
Assuming all WB and Netflix customers move to the super platform, that's a loss for Netflix (assuming the super platform doesn't significantly reduce their costs).
And the $35 might be more than some set of current Netflix subscribers want to pay, so they drop the service, so an even bigger potential loss.
Certainly, I have no desire to subsidize sports fans via a higher Netflix super package.
Everything about these big moves in the streaming space is basically to re-create the "good old days" of cable subscriptions and pay-per-view.
I think we can expect HBO streaming to continue as a premium subscription for movies and high-production-value shows. That would let everything else to land on Netflix with no conflict.