This is not an issue with the TTC. It's gov't regulations and environmental factors that result in the increased costs. You see the same issue across the country.
You are being completely Toronto centric. Just because Toronto is incompetent doesn't mean every other city is.
Look at Vancouver's Milllenium SkyTrain line.......from the day it was announced to the day of completion for an 18 km grade separated and high capacity line was 28 months. Toronto wouldn't have been even remotely close to finishing the envirornmental review. The most noteworthy point is that guess who didn't complain?..............the environmental groups.
Why?.........because they knew that it didn't matter what was found along the route wouldn't make any difference. What if they found some concern was irrelevant as it's not like they were going to close down the Lougheed highway. This is the same as Eglinton where a review should be irrelevant as the road is already built. The environment groups knew that the reviews governments undertake almost never have anything to do with concerns but are used as political footballs to stall a project. It's exactly the same as what Ottawa does when it needs a problem fixed...........it doesn't fix the problem but rather does a Royal Commission which takes off the political heat and leaves the problem for the next government. Toronto could fill three floors of Robarts for the number of reviews and studies it's done on the DRL.
This is made worse by the fact that after these make-work project reviews they come out with plans that are undoable and assume that money is no object. The latest example is the latest DRL study which brought the project in at $8 billion. That is an ass backward way to do infrastructure, You set a price and then tell the consultants to work within it. You don't just tell them to create a fantasy network as if money is no object which again takes the heat off the local politicians by them being able to say it's either too expensive or the senior levels of government should pay.
For the $12 billion Toronto has budgeted for rapid transit for Eglinton/Spadina/SRT it should EASILY be able to double it's current subway/Metro system.
It is comical, embarrasing, and downright pathetic how Toronto and the TTC call the SRT an obsolete, expensive technology yet that exact same technology in Vancouver has proven itself to be very very reliable, fast, safe, comfortable, and cost effective to both build and run. Transit "professionals" may talk about how SkyTrain is too expensive and proprietary but while they are giving excuses as to why they should not use it Torontonians are wallowing in a transit system that is coming chugs from station to station, Vancouverites are already at their destination.