Is it just hard, or downright impossible since IPv4 depletion?
But if you're going to start an ISP, you'd best do it in the next few months. Europe and Asia are already screwed.
I'm with a ~6 month old ISP here in New Zealand, by default everyone is behind CG NAT, but you can request a public IP.
I'm one of those people unfortunately, mostly because my DDoS mitigation and countermeasures are not IPv6 ready- and I can't risk my companies business since it's all public facing ecommerce. :\
although, yeah, you could put everyone behind a NAT for ipv4, but then you have the same problem as with Quatar (or was it Saudi Arabia) where masses of people are blocked because they all exit onto the internet from the same place.