If COR wasn't an issue below 16 degrees of loft there woudn't be any guidelines.
COR could have been an issue before the current limitations were set, but based on the smash factor numbers, I just don't see it. If you have some other data that shows that there is significant difference, I would love to see it. But I have not seen any to indicate that this is a big issue.
As Garland has implied, all substance have COR. It is wrong to say that persimmon does not have COR. It is just a question of how much. And the smash factor number says that difference in COR between the current generation of titanium head and persimmon drivers are negligible.
A titanium driver/graphite shaft is lighter, and larger. It allows the grip it and rip it crowd(everybody who puts one in their hands) to do so with abandon because much more of the face is usable, and hot, and impossible to miss.
I am afraid you are reading too much into a typical marketing jargon. While it is true that lighter drivers allow you to swing faster, most tour players use heavier (and shorter) shafts and driver heads (they are pretty strong guys). And we are talking about 5 or 6 mph difference, and less if Chad used a longer steel shaft. And I do agree that the shaft makes a significant difference. I am just not convinced that the titanium head does. And the data you are referring to certainly does not.
Notice the heights of the balls, there is only one yard separating them, yet there is a 900 RPM difference, a factor of where the weight is located in a persimmon head.
That could be true. But you have to also remember that a typical driver used by a pro has been customized over many many hours of customization sessions with radar and a team of engineers. For this test, they just grabbed an available persimmon driver and let Chad go. While you many not get the spin to go away completely, but with proper customization, you can get the 900 RPM difference down to 200 or 300.
Look at the yardage Campbell got with a balata/persimmon combo and then the mulitlayer/persimmon combo. There is only a 7 yard difference.
Look at the difference between the persimmon/multi and the ti/multi, there's a 37 yard difference. The ball is a small part.
I think that is because Chad is getting a ton of spin with the multilayer ball. If he got that down you will see more difference. He is know for hitting a low ball and he probably has a natural swing that puts a ton of spin. If you tested it with someone with more upsweep swing (Adam Scott for example), I think you will see a much bigger difference.
This is just one test, not a very scientific one either. It seems like they only put a single data point in the chart and not average. We have no idea how many balls Chad hit in what condition. Adam Scott did a much thorough test hitting many balls and there was only 3 or 4 mph difference in swing speed with about 5% difference in the distance. But he lost a lot (+10%) of distance when hitting with old balatas. Adam actually hit longer with the persimmon and the new ball vs titanium with the old balata.
I have seen other tests where ball plays a much bigger difference. Again, I would refer you to the Smash Factor. Persimmon was able to transfer just as much energy as Titanium, even in this small sample.
You can't make a persimmon driver work like a new titanium driver.
The Smash Factor numbers say otherwise. Again, the real difference between titanium and persimmon is MOI. You will lose much more distance if you hit off-center with persimmon compared to titanium. But if you hitting square, you are not going to see that much difference.
They don't, we're not. End of story, for me at least. I'm not even going to get into the hundreds of people who I've seen gain impressive distance.
True, but most likely those gains are coming from balls and shafts rather than the driver head, if hitting on the sweetspot. What most people notice with the titanium head is how little distance is lost when hit outside of the sweetspot.
With the pros, the fact that the today's metal heads are much more customizable is probably the main benefit since they hit the sweetspot so consistently.