Just some observations from sailing on Lake Michigan...
I race J/30 Class
when I can (maybe once a year), and PHRF most of the time. So far, I haven't found that the class main has hurt us against other boats.
Two years ago we sailed the NOOD here in Chicago with a 14 boat PHRF section. J/30s were the slowest rated boat racing, including a brand new J/92S with a very good sailmaker. J/30s placed 1st and 2nd in section.
Last year we were again condemned to racing PHRF. This time the wind was light, and the 30s placed 7th and 8th. No difference in sail technology could have changed that outcome.
Our toughest competitor here is an S2 9.1. When we sail well, we beat them. When we don't, they beat us. Again, from what I can tell, a change to a high tech main wouldn't change that.
When I have priced new mains, the difference between a kevlar and a dacron main has been about 25%. For me that's significant (with a kid in college anyway)... and for no real difference in race results seems like the wrong place to spend my $.
Ullman sailmakers has done well in lots of different classes. In the Melges 24 class, they choose to construct dacron mains when they could use laminated sails. Technology is a good thing (I'm in computing), but just for the sake of technology seems to be unwise.
I do understand that having to buy 2 mains to be competitive is really expensive. I suggest however that the class main is perfectly fine, and perhaps more adjustable than a kevlar.
Anyway, my $.02