Why is there no discussion about extending the Sheppard line west to meet the Spadina extension? At a distance of slightly more than 4km, it doesn't seem unreasonable and it would create another transit hub at Downsview.
Oh, there's been plenty of discussion about it...
I support it, and I think most people by looking at the map can agree that it makes a lot of sense, but where do we find a few billion dollars to do it? And there are far, far more critical transit projects that need money--the relief line, new subway cars for Line 1 so that the TRs can move to Line 2 for the Scarborough subway extension due to the need for ATC, accessible subway stations+second exits, Eglinton East and West LRTs, Waterfront West and East LRTs, Sheppard East LRT, new streetcars for the existing downtown streetcar network, new buses, a new bus garage, better maintenance of existing vehicles, better service on streetcar/subway/bus routes across the city, streetcar and subway track and power maintenance, enhancements to Presto, two-hour timed transfers, discounted fares for people with low income, co-fares/fare integration with GO and other agencies, and more. Those, in my opinion, are all of significantly higher priority than connecting Sheppard-Yonge to Sheppard West station...and keep in mind that project wouldn't take the place of one of these other things, it would take the place of several, or as much as half of that list.
When you look at it that way, unfortunately it is rather unreasonable. I really want that connection made, but until we get all of these other critical things done and have a properly functioning transit network on the existing portions of the system, it's foolish to spend tons of money on something like this. I think if so much money had to be wasted on the Scarborough extension, this would honestly have been a better use of that money--though still a waste--but alas, we chose to dump money into that pit instead.
Also, once Line 5 opens there will be a frequent, high-speed, underground connection between Eglinton W (or whatever they're calling it now) and Eglinton, which is much further north than Line 2 and a bit further north+faster than the 512 streetcar. That's a significant improvement for people who need to go east/west in the northern portions of Line 1.