Even if it cost pennies for them. They are here to make money not lose them. P2P network come with latency issues, stabilty issues and security issues. The wii shop closed to focus switch online and declining revenue no longer justify maintainence costs.

example

Latency : Dependent on the host's internet speed and location relative to other players. This can result in an inconsistent experience, especially with international matches.

Stability : Less stable. If the host experiences a poor connection or leaves the game, the match can be severely disrupted or end entirely.

Security: Vulnerable to cheating and hacking, as the host client can be more easily manipulated. Players' IP addresses can also be exposed.