From what I've understood it's not being blocked due to the any landowner refusing to give up land, in a technical sense, but rather is going to court over environment concerns that Bradley extension "could cause". Just refusing to give up land isn't a solid legal argument, London could use powers under the Expropriations Act to get what land it needs. However because they've gone the environmental route it gets very messy and very time consuming. Environmental legal cases can go to astronomical amounts before even going to court, and even know who knows what rare earthworms or flys need protection...
In most recent City budget, which included capital projects Bradley west extension isn't mentioned, meaning either it's planned further than 10 years out, or due to court cases they cannot anticipate when they could begin construction.
Either way its bullshit. It's been on the books for over a decade, was planned shortly after London annexed Westminster township, and would be allow better circulation of traffic. While things are only getting better, which Southdale now 4 lanes and Commissioners 4 lanes next year, look at the north end and all its cancelled east-west arterial (Cheapside-Wharncliffe, Sarnia-Huron, Gainsborough-Windemere) and how poorly traffic circulates.