Define head wear.
This whole thing reminds me my short time at TH where every poor guy showed a photo of their deck's head, the reply was "this head is crap".
A lot more things matter than the tape type when talking about head wear. I bet you there are quite a few type I that are head grinders, more than any type IV.
Then, it's the pad's pressure force. It's not the same for every cassette. Then again, it's the back tension force. It's not exactly the same even across the same deck model. The final finish of the head differs between batches. It's the overall condition of the transport. And so many factors don't come in mind...
One need to make exhausting tests to come to safe conclusions, and I don't think there are such tests published.
Last, I think if a type II or IV were eating a head faster, the deck manufacturers should have mentioned that for warranty reasons.