And no, YC hasn't been on my mind at all, nor is this a 'told ya so' to PG. I do hang out on HN under a different name though so I thought I'd post for anyone who was feeling frustrated in their own journeys since I know that in-the-moment rejection can sting disproportionally more than during the time that it actually matters, i.e. the rest of your life.
Sheesh, did you work that into your pitch? I understand that you're feeling hot right now, but leave your unfounded technology biases out of it.
Aside from that, I'm a huge fan of abstracting commonly made and agreed upon technical decisions further down the stack, making higher level development much simpler and less technically challenging - which is from my understanding what RoR was/is largely about. That's not to say that RoR as a framework isn't in and of itself a technical achievement though.
If you had pitched with the same co-founder and same idea and still got funded, you could have given PG a big 'told ya so', but different idea, different co-founder, is really a different sitation. Plus, I'm sure YC doesn't invest in many ideas/people that they wish they could, as they have to make selections on very little details.
Out of curiosity, what stage are you at with the new company? Did you close your round with a working prototype? moderate user traction? existing customers?
Again, congrats on the funding. Best of luck with the new biz.