[ssiguy]

GO has nearly a 1000 bi-level cars and to sell them for pennies on the dollar just to get EMUs would be a horrifying waste of taxpayer funds.

Also, compared to most suburban rail systems, GO stations are fairly far apart so the slightly slower de/acceleration is not as big a deal as on most systems. As noted, EMUs require more maintenance and if one section goes out the whole train has to be taken out of service. Also due to GO carrying passengers nearly 100 km, electric locos are the better choice as comfort becomes more of an issue on long hauls and locos are smoother and quieter than EMUs.

I'm quite sure the GO will be eventually moving over to EMU for it's core inner city routes as they have to begin to retire some of their current bi-levels but there is no rush to do so now, They will probably keep their bi-level electric locos for the longer distance and express routes. In transit, there is no such thing as one-size-fits-all.