pay for colocation with BGP access with a fake ID or compromise any BGP-announcing router in the entire world (I've found cisco routers with announce access, with default credentials, on networks that don't do any kind of prefix filtering many times before) and you can trivially MITM most any network in the world with very minimal impact. I recommend you watch to Kapela and Pilosov's talk from DEFCON 16 to see how easy it is: https://www.youtube.com/watch?v=oWdjsfsS_Do
or if you don't want to do it via BGP announcement you can just compromise any of the devices that are along the route between the client and the server. BGP is the rocket launcher of worldwide circuit compromise, but there's many other guns you can pick up
Nope, nothing has changed! You can still MITM with BGP in the exact same manner! BGP is like SS7 -- once you get access to use it, it is wide open and completely insecure and no effort has been made to use it. All its security is predicated on the idea that anyone with access will have too much on the line to abuse it, and responsibility for monitoring announcements for your own IP is considered your own problem. Ask around -- how many people in your social circle of admins keep track of rogue announcements? How many would notice if this were going on?
More colocation facilities in the US and Europe now do prefix filtering at egress - but this matters little, as there are still quite enough that don't. In contrast, there's virtually no prefix filtering in Africa or Asia (remember when an accidental BGP announcement from Pakistan killed YouTube worldwide?)
How hard is it for an attacker to do a MITM? Would the attacker need physical access to the user's wifi router?