The answer for all of these is RER, not subways, subways, subways.
How backward is the GTHA? The only people pushing for subways are self-centred entitled types with no understanding of what the RoW is doing. Small extensions of present subways, yes. But the subways towards to the core are already past saturation point. Just leave them as is, they're already tapped out, save for perhaps signal and control tweaking, and bypass them with...wait for it...duh...other forms of transit.
Which go line directly serves the STC? I can understand Richmond Hill or Vaughan, and the only reason I support the Yonge North Extension is because a lot of people live along Steeles and having a station there would be beneficial for commuters. (and again, this line should come AFTER RLN)
As I said before, not everyone is going downtown, a lot of people's commutes are made easier by a TTC connection to the STC. Many go to places along the BD line, some even catch the Yonge line north to Eglinton-Yonge.
If Scarborough Town Centre is on the same 'corridor' as the Bloor/Danforth line, I guess St Clair station is on the same corridor too.
Why should I have to transfer? The people of the Bloor/Danforth Line deserve a transfer free connection to St. Clair centre. It's only fair.
Seriously?!!? I'd think the transfer would add some excitement to the torture that is their commute.
If a long commute on a peaceful transit system makes their lives 'difficult' perhaps the problem is their perspective.
If they don't want long and boring commutes, perhaps they should
a) Consider moving closer to the location they're commuting to
b) Bring along a book, smartphone, etc. for amusement
What next? Will the TTC have to hire clowns and performers to ensure the people of Scarborough have entertaining rides? Perhaps we should hire 'carriers' to literally carry people from the RT to the subway? It's probably cheaper than this project.
The rationale for this extension has moved well beyond insanity.
I'll have you note that I'm in support for a St. Clair Streetcar extension, but this is besides the point. There's no rapid transit along St. Clair so that has nothing to do with my argument.
Transfers != excitement, Transfers = "Jesus Christ, why must I waste my time doing this?". Not everyone can afford to live in Old Toronto, and most commuters do what you suggest. Transferring means they have to stop what they're doing (ie reading) and move to another location, but many times it's difficult to even do those things because of how busy trains can get (and lack of cell service in tunnels).
There are good reasons for the SSE, one of them is the fact that shuttle buses will not be needed while an LRT conversion occurs. Say buses are to run at frequencies of every 2 minutes all day during the week and 3 minutes during weekends (frequencies would be greater during peak times, while less during off-peak hours). If traversing the corridor fully takes an hour (kennedy-McCowan-Kennedy), 30 buses are required to be running during weekdays and 20 during weekends for 16 hours each day for 5 years. In total, if it costs the TTC 25$ for a driver, 5$ for supervisors, 20$ for maintenance, and 10$ in fuel (10L for the full trip) per hour, operation costs per bus are 60$ an hour, 28.8K per weekday, 19.2K per weekend day. In operational costs alone, this setup will cost 50 million dollars over 5 years, not including the loss in ridership costs (50M$), hiring & benefits costs (~25M), new bus costs (30M assuming 30 buses), new garage costs (100M), lost productivity costs (170M), congestion charges (due to new drivers to downtown (Hard to put a number on it, 5K users get cars and drive it downtown, I'd say that will cost people 175M just in operating the vehicle, plus extra congestion costs on the DVP)), for a total of around 600M$ in potential costs for users and the economy of Toronto. Lost productivity costs by removing the transfer at Kennedy pay for the subway in 60 years without factoring in increases in wages, and a decrease in TTC staff save money as well by streamlining operations. There are benefits, they just may not be seen.