Now I wonder how many people did this and got away with it.
There's a study¹ that determined the fate of 350 manuscripts rejected by the Annals of Internal Medicine. They found that 69% of them were eventually published in another journal. 70% of those were published in more specialized journals with lower impact factor.
It appears the reviewer took a similar approach. The manuscripts were published between 121 and 1792 days after rejection, with a mean of 552 days. The letter to the plagiarist says the article was published "a few months later" so that would be approximately 90 to 120 days?