They don't have to anymore. Most of the intersections are built to the newer standard where they can just close the streetcar lane, excavate the top layer of concrete, replace the switch and pour in new concrete. Should only take a weekend. They just have to cut that section of the rail and weld in a new switch.Keep in mind other systems have proper lights to tell the driver of the streetcar or LRT that the track is aligned for them and most of them are newer then our current network is. I doubt the city would be happy if the TTC decided to rip up all the intersections and other places to replace the switches.
Of course it would be easier to do when they redo all the intersections again in 15-20 years.