The only real, long-term solution will be for offices and businesses who employ people in the 905 to move out of the 416 and setup shop closer to the 'burbs, where most of their workforce comes from. Sadly, that will take decades.
Seriously??? People will live where they want and can afford. People will work where they find a job where they want/can/need. To expect 416 people to only work in 416 & each region of 905 to do the same is an unrealistic fantasy.
The best way to improve the situation is to break down the transit bureaucratic silos and worry more about tax funding operations and less about capital improvements . MetroLinks was supposed to do that, but became another level of bureaucracy instead. If GO & UP Express operated within the City as an integrated direct transfer system with no fare increase, you could transfer to GO at Leslie Station (Leslie & Sheppard) and be downtown in 1 stop, acting as an effective Yonge relief line. Transfer to GO or UP Express at Dundas W and be downtown in 2 stops, relieving the Bloor lane and avoiding the need for a west downtown relief line. Transfer to GO at Main Station (Danforth & Main St) and be downtown in 1 stop, relieving the Danforth line and avoiding the need for the east relief line. And this is just the beginning of the efficiencies that could be found in an integrated transit system.
All this infrastructure is already in place. Capital improvements would only be needed to make good GO/TTC connections at these stations, to add rolling stock and to electrify GO and twinning of the Richmond Hill GO tracks as least as far as Sheppard. But none of this is as sexy as announcing the construction of a whole new line, but could probably be done for less than the cost of the 1-stop Scarborough subway (which will actually reduce service as its replacing the Scarborough RT). The Feds would need to wrestle rights away from CN (who barely use them within the City anyway and got them for free from the Gov't back in the 1800's). The rest of the monies set aside for capital funding could be invested and allocated out as annual operations funding.
Right now if you commute twice a day, 5 days a week using tokens or Presto, you need to do 9 extra rides per month to break even on the cost of a MetroPass. If MetroPasses were subsidized to cost less than the cost of regular commuting, they would be in the hands of way more riders, who would then also use the system more in off-peak hours.
So why hasn't this happened? Because each separate agency does its own long range planning and talk to each other much less than they should. Because each silo wants to protect its own interest and cost/revenue sharing, and this kind of system would be extremely complicated to manage from separate budgets. And because every elected official has a brilliant new way of promoting themselves by fixing transit and Council keeps flipping back and forth.
Rant Over ... I just get pi$$ed off hearing about more taxes/tolls to fund inefficient improvements that end up doing more damage than good when it could be handled in a much better manner. If only we could break the back of the intransigent bureaucratic structure of our transit organizations.