Well technically they don't charge a different price if you have a public ip or only a private IP on an instance. However even if they factored in that some high % of all EC2 instances will have a public IP and that's "part of the cost" what I'm really asking here is if eventually that cost will be so significant that they actually need to raise instance prices solely because of the IP price.

If that's the case, then it may make sense to lock the instance price down, and start charging for in-use v4 IPs, not just unused allocated ones.

Let's say the next block of 1 Million IPs that AWS wants to buy from say, GE fails to go through, and AWS is looking at a pool of 500K IPs starting to shrink at the rate of 30k per day. The only way to ensure they don't run out would be to separate the price out and jack up the price considerably so they don't run out.

What I'm saying is that at some point, WHEN the number of IPs that people want outpaces the number AWS (or Google or other cloud provider) can obtain from other companies, they will be forced to change something.

What would be interesting would be to see AWS etc, to try to get their customers to migrate off IPv4 for administrative and back-office services since there really isn't a strong reason to have VPNs and SSH or RDP sessions backed by a v4 address.

Has the price per elastic IP ever gone up though on AWS? I don't think so, but you'd expect price to rise over time as less addresses become available.