The root cause for so much of the subscription ruckus, I think, isn’t that 30% number — it’s that Apple pulled the rug out from under some major apps after the fact. And unlike nearly every App Store rule change in the past, this is a major change that developers couldn’t have been reasonably expected to anticipate, and it’s not based in any practical need for the health of the Store or the platform (malware, abuse, etc.).
I’m not sure we even disagree on this. I concur that worst aspect of these new subscription policies is that something that used to be allowed now is not. It has a bait-and-switch feel to it.