I guess it's partially because ISPs are perfectly happy selling crippled internet connectivity as the base service and charging hefty premiums for "luxuries" like static IPs. It has also become common to only offer static IPs to business customers.

IPv4 addresses have run out, everything has been allocated, and they are now being traded.

IPv6 is slowly growing in popularity. Google stats are close to 50%. If your ISP has IPv6, you might be accessing Hacker News with IPv6 since they added support recently.