I never said the profit had to come directly from Mac Pro sales, just that the profit would be a consequence of the Mac Pro updates.
With that clarification I agree with that part.
In fact, the evidence suggests that it's currently not the case - what's the evidence? Why, the fact that Apple hasn't updated the Mac Pro. Either they know it wouldn't maximize returns at this time, or they are a bunch of dummies who don't see what you do.
In fact, I thought I had made it pretty clear that there isn't any evidence either way, and my opinion is my opinion. In case I haven't made it clear enough, let me do that now.
There isn't hard evidence either way. My personal opinion is that it would make more profit than if the resources spent on development were allocated elsewhere.
And I disagree that Apple not updating is "evidence" of anything. In general they've done a good job of running the company overall, but that doesn't make them infallible. They have made some pretty giant mistakes in the past. No company ever knows what will "maximize returns", it's all speculation until they actually take action. They should know how much it would cost to update the MP, but the amount of increased sales is a guess, even for them. Until they do it, it's a hypothetical. And even after they do it, they'll know about direct profits, but it's still hard to measure what indirect profits are due to it. Honestly, I think a major factor is that Steve Jobs just never liked the Mac Pro, regardless of whether it sold or not...and now that SJ is no longer in charge, I think things may change (again, my opinion, so sorry you don't get any "evidence").
It's entirely possible that there's no way Apple could do a MP update such that the profits are worth the costs. But I just don't buy that there's any "evidence" for that at all. You have an opinion, I have an opinion.
We'll see at some point this year when Apple releases an update, discontinues the product, or does nothing.