Anything extending the life of IPv4 is actively harmful.
(Like I said last time this was posted.)
The most important problem with IPv4 is that it mandates 1:N NAT configurations that break direct connectivity between devices on the Internet. Yes you can traverse NAT but it's an ugly and often unreliable hack. This of course is because the address space is too small for everything to have an IP, whether global or 1:1 NATed.
Difficult peer to peer connectivity means everything has to have a server. You can't just write communication apps that... communicate. The added cost here is enormous both in money and in privacy/security.
IPv4 is also too small for private networks. Corporate networks are often full of hideous hacks like multiple NATs that negotiate interoperability between networks with overlapping 10.x address spaces, "theft" of unused IPv4 space such as US DoD addresses, etc.
(Like I said last time this was posted.)
The most important problem with IPv4 is that it mandates 1:N NAT configurations that break direct connectivity between devices on the Internet. Yes you can traverse NAT but it's an ugly and often unreliable hack. This of course is because the address space is too small for everything to have an IP, whether global or 1:1 NATed.
Difficult peer to peer connectivity means everything has to have a server. You can't just write communication apps that... communicate. The added cost here is enormous both in money and in privacy/security.
IPv4 is also too small for private networks. Corporate networks are often full of hideous hacks like multiple NATs that negotiate interoperability between networks with overlapping 10.x address spaces, "theft" of unused IPv4 space such as US DoD addresses, etc.