IPv4 won't disappear or exhaust. It will fade out like a white dwarf, but it may well be still in use, 20 or 30 years from now. CGNAT at client side (already in

IPv4 won't disappear or exhaust. It will fade out like a white dwarf, but it may well be still in use, 20 or 30 years from now. CGNAT at client side (already in widespread use) and server-side public IPs that cost money every month will keep usage of IPv4 addrs in check. Of course, richer protocols like P2P will have to go IPv6. (Back in 1993, when a guy said that MS-DOS would be in use by 2000, I laughed at him. I made serious money on MS-DOS+xBase until 2005!)