Carrier grade NAT puts thousands of users behind the same IP address - that's what it's for.
You can't put 10k people behind each IP and not have problems. That's 6.5 ports per person, you need one for each connection. Pretty much any website will have issues with that little connectivity.
> Carrier grade NAT puts thousands of users behind the same IP address - that's what it's for.
It doesn't have to. 100:1 would work just fine. With IPs being about $25 each that's an acquisition cost of less than a dollar per user.
> That's 6.5 ports per person, you need one for each connection.
That's not how connections work. Each user could make a million connections as long as they're spread around different servers. The 65k limit applies to simultaneous connections to a single webserver. Only the most-connected server matters, so probably something at google/youtube/facebook, and even then most of those servers have multiple IPs.
You can't put 10k people behind each IP and not have problems. That's 6.5 ports per person, you need one for each connection. Pretty much any website will have issues with that little connectivity.