This is nothing new - the market for coupes has always been hotter for coupes than for roadsters. Why? Because the coupe is rarer? Better track weapon? Better looking car (to some)? Probably some of all of this, maybe other factors too.
But it's not like the roadster is an inferior car. It seems like the price gap is widening - making roadsters a ridiculously great buy right now. For example...
Nice coupe, 43k miles, hammers for $42k yesterday at BaT, despite potentially value-sapping features like dark sepang interior paired with Interlagos, Madeira wood trim, & nav...
https://bringatrailer.com/listing/2007-bmw-m-coupe-11/
Today, a beautiful Imola roadster, only 25k miles, hammers for $24,500. Talk about an awesome buy!
https://bringatrailer.com/listing/20...-m-roadster-9/
If this keeps up, I gotta find a place to park a roadster at home, to go with my coupe. So much bang for the buck.