I am not sure if he would.
As a person who is entirely pro-immigration...........
Uh, yes he would.
That's too aggressive a number.
The cost of readying infrastructure for that number would be enormous.
It would also have huge implications.
Take a look:
If, the Goldenhorse took only 1/3 of that number (well less than our current share of new immigrants)
You're talking about about increasing the population here by 20M, to roughly 30M
That's staggering.
Even with large-scale intensification it would near impossible to do without going well into the Greenbelt for development.
Toronto already has notoriously bad commutes.
The O/L / Relief Line isn't really to address growth like that, its to catch us up to where we need to be now; the same could be said for the base level of GO Expansion/RER
You're talking about a scenario with a GO Midtown line; the missing link, GO to Bolton, GO to Uxbridge, GO to Orillia, and GO to Brantford.
You're also talking about a completed Sheppard Subway (Sheppard West to STC); the relief line/OL going to Steeles, not Sheppard, and likely another Relief Line on top of that.
Never mind a Line 2 extension to Mississauga and a bevy of LRT projects.
This isn't Billions or Tens of Billions is well over 150B new transportation infrastructure alone, in the GTA, alone.
That doesn't address sewers, water mains, hospitals, schools etc etc.
****
Now imagine how the places that get the other 2/3 of immigrants will feel.
Some small communities would love a few hundred or thousand new citizens.
But are Haligonians ready to from 400,000 to 2,000,000?
Vancouver could stand some additional intensification; but even a wall of hirises in North Vancouver isn't going to get you room for an extra 4,000,000.
Montreal/QC would have huge concerns about the French language being swamped.
You need to picture an Edmonton and Calgary at 4M+ each and likely Winnipeg too.
I think you need to restrain your sense of scale.
100M by 2100 is believable (whether we want that is a different question)
100M by 2080 is pushing the boundaries of plausible and unlikely to receive a positive reception.
But by 2050? Next to zero chance.
Too ambitious, too lifestyle altering, too drastic, too soon and too expensive.