There are numerous attack vectors that can expose you to a man-in-the-middle-attack in this instance:
A Rogue Access Point. Someone impersonates your AP and forwards the traffic on to the AP, thus allowing them to perform a man in the middle attack on your network traffic.
DNS-based attack (as pointed out by schroeder's comment): What DNS servers are you using? If those DNS servers are compromised, they can redirect you to a man in the middle attack. If you're using your local router as a DNS server, it could be compromised to point to malicious DNS servers, among other methods. If your local computer is compromised with malware etc, it could be pointing to malicious DNS servers (although int his case a man in the middle attack might be superfluous, since they're already in your computer)
The other end of the connection. If the endpoint network you're connecting to has been compromised, the man in the middle attack can be conducted from the network on the other end. This would be a less realistic issue in the case of large sites, but for personally-operated servers/sites this may be a viable attack vector.
But yes, as you point out there is no way for a random entity on the internet, without access to a privileged position like an Internet Exchange (IX) or an ISP, to carry out a man in the middle attack at whim. They would typically have to compromise, somehow, the local network on either end of the connection to launch such an attack.