Blue Jays record during AA's tenure:
2010: 85-77
2011: 81-81
2012: 73-89
2013: 74-88
2014: 83-79
2015: 93-69
Fans like jaysblue conveniently forget that prior to that 2015 trade deadline, the general fan consensus was that AA was a failure and needed to be fired. He had made a ton of "blockbuster" moves over several seasons that added significant salary to the payroll but barely moved the needle at all in terms of the team's playoff aspirations.
It's kind of funny how in half a season in 2015 after one magical run he went from failure to "best GM in the league" according to Jays fans. Yes that 2015 team was underperforming their Pythagorean expected record in the first half of the season so it's not surprising that they went on a run, but it's also entirely possible that one or two injuries happen and the team slumps and that run never even materializes at all. Everything fell properly for the Jays, including scrubs like Chris Collabello emerging as impact bats. You can give AA credit for 2016 as well (after he left) since it was still essentially his team, so you can conclude that his "build" in fact succeeded as it led to two playoff appearances, but for all that work he put in over ~5 seasons all he managed to build was a team with a two-season window of contention. His roster had zero possibility of contention past 2016 because even in 2015 all of the best players on the team were seconds away from inevitable collapse (which is exactly what happened - by 2017 the ~five core position players alone had seen a collective ~66% drop in their fWAR from 2015).
The other thing that doesn't get brought up is that the AL East was significantly weaker in 2015 than it has been the past three seasons while Atkins has tried to contend. Only the Jays and Yankees finished over .500 in 2015. Take a look at the past three seasons and there are 3-4 teams out of 5 in the East who have been legitimate playoff teams. The Yanks are currently in last place and they're 4 games over .500 which is absurd. This means that Atkins' road to wins has been SIGNIFICANTLY tougher.