Imagine if the Eglinton subway was built instead of the Sheppard line? I highly doubt the Eglinton subway would be extended in both directions at the same time as the costs would be insane.... I would imagine in the 9 billion, maybe 10 billion range for the subway extended to PIA in the west and Kennedy in the east. I know some of you who are pro subway will hate me for saying this, but not building the Eglinton subway years ago has been a blessing in disguise. Why? Because at least now, Eglinton Ave from Kennedy to PIA will have seamless transit. I'd take that over the subway any day of the week.
If the Sheppard subway was never built we'd probably have seen a proposal for a Sheppard LRT line spanning from Downsview to Meadowvale.