Peter F's line -- ie a square path with a persimmon outdrives an over the top hack with an M2 every time -- rings true from my experience.
Also true from my experience:
1 - a well struck persimmon driver travels about 10-15 yards longer than a well struck modern 3 wood, but about 15-20 yards shorter than a well struck (fairly modern, 44 inch) driver
2 - persimmon is "well struck" about the same % of the time as modern equipment; but mishits aren't nearly as noticeable with the latter
3 - I compiled a persimmon and blade set for an old, long hitting friend. He still hits it farther than me, but the yardage difference between us is less with persimmon than it is with titanium...with the difference decreasing further as lofts go up, ie we hit our 5 woods about the same
Just an aside: while I'm no club collector, I do have a couple of old sets and a new one; besides differing lofts (and to some extent shaft lengths), the biggest difference between old and new is the lie-angle - the older clubs tending to have much flatter lies.
The irony of technological advances, i.e. irons have gotten more and more upright in response to so many average golfers having an upright/over the top move...but the upright lie angles now only *reinforce* this over the top tendency; and lofts getting stronger and stronger so that average golfers see their iron shots fly longer -- with the result that pretty soon they'll hardly be any irons left in their bag, as average golfers migrate to hybrids because their modern 5 irons have the lofts of old 3 irons, which they can't (and never could) hit
I don't know if the game is getting harder or easier to play, but for my tastes it sure is getting *uglier* (re equipment). Maybe that's one reason we're getting so many stunning and natural-looking new courses, i.e. when you have to look down for 4 hours at toasters and shovels instead of crafted wood and steel, you need to have *something* beautiful to look at