I will say, except for a very few, more gains are achieved by training the nut behind the stick.
If I could spend $xxx,xxx and win US Nats, sign me up.
But, I KNOW that a good pilot could fly, say, a well prepped ASW-20 and kick my butt flying in ANY new glider most days, thus pilot training is worth it first and foremost.

(Yes, I know what you fly, yes, well prepped it's still a great sailplane......).