57years is indeed insane! But not quickly! Other than that 57-year old plan (and there have been several versions of it over the years), the key element that's been added is the LRT over the new Champlain bridge, to the south shore. Planning for that was was going big-time by 2007 - but I think the AMT studies on it were going on for years prior. I seem to it being listed as one of the "Grands Projets" on the AMT website for years and years (digging through the Internet Archives - yes it was mentioned back as early in June 2002 as "l’axe de l’autoroute 10 entre Brossard et la Place Bonaventure à Montréal". I hardly suspect it was a brand-new idea even then!
Construction on the LRT section over the St. Lawrence started in 2015. The whole thing being finalized and integrated into a single line was relatively quick - but if you ignore the half-century of planning that preceded it, you are really seeing much greener-grass next door.
Meanwhile, look at the status of the three Montreal projects in page one of this thread, nearly ten years ago that some in this Forum were using of proof of how far ahead Montreal was of Toronto. All were to be completed by about now. Status? Blue line 5-km extension - might start construction in 2020 and be complete in 2026. Yellow line 5-km extension - dormant. Orange line 10-km extension - the bit to Bois-Franc is dormant, and the rest seems forgotten. Meanwhile the Spadina subway extension is complete, the UP Express has opened, 19-km Line 5 Eglinton - which wasn't even mentioned on page 1 - should be open in 2021, and the 11-km Line 6 should open in 2023, of our Premier doesn't manage to mess it up.