That's fair, and I agree this definitely predates Atkins. The Jays haven't really been a true pitching-development factory under any regime for a long time. AA probably came the closest simply because he drafted so many arms. Stro, Sanchez, Osuna and Boyd all came through that system, with Thor obviously being traded before reaching Toronto. And while Morrow was acquired, the Jays deserve some credit for helping turn him into a very effective starter for 2-3 years when he was healthy.
Even before that, JPR had Marcum, while Romero gave them 2-3 genuinely strong seasons before everything fell apart. And going back to Ash, you had Halladay, Carpenter and Escobar, with McGowan drafted late in that era and developing under JPR.
So I completely agree this isn't some uniquely Atkins-era problem. The Jays have struggled to consistently develop pitching for decades. Where I still think the criticism is fair, though, is that Atkins came from an organization that was arguably the best in baseball at finding and developing pitching, and after more than a decade here, with far more resources and a state-of-the-art development complex, Toronto still hasn't really created a sustainable pitching pipeline.
That doesn't mean the standard should be Cleveland or even Tampa. Very few organizations can consistently do what they do, and you're right that even the Dodgers have had to spend enormous amounts externally on pitching. But that's also why I think this remains one of the fairer criticisms of Atkins. Not that he failed to turn Toronto into Cleveland, but that after this much time and investment, they still haven't become particularly good at producing a steady stream of useful MLB starters and relievers.
And to be fair to Atkins, acquiring starting pitching really hasn't been an issue. Gausman, Cease and Bassitt were real strong FA additions. Ray gave them an excellent season-plus after being acquired, and trades for guys like Berrios (earlier on) worked out pretty well. So far, Soriano hasn't looked too bad, but I still think he's more of a #3/4 when it comes to a Postseason rotation. They've generally been able to build a respectable rotation by going outside the organization, so Atkins deserves credit in that area.