Perhaps it can't, but I'm sure glad we built the subway out in the following locations (all within the last 50 years):The same can't be said for subway expansion locations over the past 50 years.
The Yonge Subway north of Eglinton — 300K PPD
The Spadina Subway (to Sheppard West) — 200K PPD
Kipling station — 50K PPD
Kennedy Station and the SRT — 80K PPD
Line 4 — 50K PPD
The TYSSE — 90K PPD
With all the ridership these corridors generated (770K PPD, about 60% of the ridership of the subway today — more than the total ridership of the Chicago L and the Washington Metro), transit remained competitive throughout this city.
Perhaps density isn't the only factor.