Toronto started their rebuild after their collapse in the 2013 shortened playoffs: Nylander 8th in '14, Marner 4th in '15, Matthews 1st in '16. Its notable that they had trouble in the 11-12 season with bad goaltending and a coaching change, they did get Morgan Reilly 5th OA in '12 after that. Note they did not acquire much extra draft capital over that time, aside from the Kessel trade which they used that 1st to acquire Andersen from the ducks (for the Sam Steel pick). They got back to the playoffs in '17, and while they have been successful in them, they have been a legitimate threat since returning.
By contrast, Gorton had multiple 1st picks in 17 (7,21) 18 (9, 22, 28) and 19(2, 20) and potentially in 20 with possible Zucc resigning, or a Kreider trade. We are entering year 3 of the rebuild. I am of the opinion the rebuild started with the Stepan trade. Some will argue that this was not the start of the rebuild but an attempt at "retooling", but considering that was a failed attempt and ended with the Kravtsov pick in the following draft this season in hindsight will mark the beginning of the rebuild. Gorts collected tons of assets since the Stepan trade through Nash, McD (and JT), Grabner, Hayes, Zucc. He has used those extra assets to acquire prospects with upside, and swung for the fences with a few draft picks and seems to have hit on a few of them. We got our stroke of good luck with the Kaako lottery pick.
Make no mistake, the organization is still very young and the kids still have a lot to learn. But Gorton has put them in a position to succeed going forward, with JD's focus on improving the development path via Hartford and where many of these players are in their development now I don't think it's unreasonable to hope that the team turns a corner after 2 more years in the 21-22 season after the expansion draft. All that remains is to instill a strong, winning culture in the revitalized franchise.