In the old days, they would build huge ass buildings for the exchanges because they thought the tech needed the space. Not until around 1990 they realised it doesn't need as much space, just as big as a house. So the reason why old places get everything, because they have the room. New exchanges, they just build a little house for it. and even sometimes just use a trailer. Old exchanges = cable + adsl2+.
New ones, they only have room for the telstra one. if they have more room. other providers will fight for it, plan out the layout. and chuck it in.
I wish i lived in keilor downs where there was cable and multiprovider 2+. But taylors lakes is running on a sub exchange which is apart of a big exchange consisting of taylors lakes, sydenham and hillside. >.>