Clearly you don't understand the math here? The tunnel can cost $200 million to rebuild and the cars can be built for $500 million ish, there you go $700 million vs. the over billion dollar cost of the LRT? Adding elevators is not going to cost on the order of 100's of millions. Which as we have discussed ad nauseum would use inferior vehicles which would easily be thrown down the middle of a road and slowed down.
I don't know why an "LRV" can carry more people than the RT, as Coolstar pointed out the RT vehicles carry more people per unit length, so unless you plan on building longer platforms for your LRT (which would make the comparison unfair) then the capacity would be higher on the RT.
Just because the system doesn't exist in a TON of other cities doesn't mean it needs to be dumped, given the grades on the SRT you could probably get rid of the LIMs but again its not strictly necessary. That being said there are LIM metro systems in a number of cities in Asia, and of course we have the SkyTrain.
Finally, there is no reason you need to wait until 2027 to fix the RT, we could have done it years ago and we could still do it now, if only . . .