The influence is kind of weak, but I think you can still kind of see how the eastern GTA and western GTA have connections to the eastern and southwestern parts of Ontario, respectively.
The western GTA and Hamilton for instance, has more manufacturing, like SW Ontario. The western GTA had more "Ellis Island" style earlier 20th century continental European types of immigration, like Italian, Polish etc., just like the US (whether its northeast US or midwest US).
The eastern GTA (prior to the 1970s or 80s) was more Scottish and "Canadian". Oshawa, Peterborough etc. seem to have that character still.
The Scarborough Settler's lament, was an old song about homesick Scottish settlers who lived in Scarborough around 1840. The eastern GTA also had more farming until relatively recently (eg. Scarborough had farms up to the late 20th century).