vpn has nothing to do with ip address

As IP address has been exhausted, ISP will use address translation called CGNAT (Carrier Grade Network Address Translation). Well, this is nothing new. Even in 1st world countries are also having these. Like some say, the ISP should reduce rate because they can serve more customer with no additional cost on IP addresses.

Major side effect would be you cannot have port forward or have anyone connect directly to your computer without using a VPN.