For me the cost isn't the main concern, it's the name collisions. I can easily obtain a short, memorable, and descriptive domain in a reserved TLD, but I probably have to find some obscure *.dev domain name because I'm competing with the entire world. Not the end of the world, I know, but I think it kind of defeats the purpose of reserved TLDs.

You'd be surprised how many short, memorable domains are still available on new gTLDs. E.g. there are several times more possible 4 letter strings than total .dev registrations that even exist. And if you're willing to use numbers this gets higher, let alone 5 characters or more.