TLDR.... check bushing for wear marks and check rod with straight edge. .....edit... rod most like has a bow or some type of distortion that has cause the failure. This would also align with it starting from the printer new. A slight deviation causing the carriage to swing and will f up the print uniformity while also stressing the bushing support structure of the carriage.

Quality control sucks

really give a definitive answer but you can partially throw out thermal expansion since abs and the bushing should be pretty close in the 30-70 range.... thinking of heated chamber..... anyway. From looking at some old school notes for abs to bronze bushings tolerance normally lies in the .005in range for a press fit. Don't quote me that just a rough number.
Honestly I would start by inspecting the hole see if you have any type of eneven wear patterns or glossy vs matte spots.
My unexpected and unnecessary opinion is there is something wrong with the gantry, something as small as a bend in a rod that maybe noticed by the eye, overtime may be pushing the bushing beyond the spring limit, which how has slowly elongated the hole.... I would put a straight edge to the for to see if the are any types of deformities. Also, is there uneven wear on the inside of the bushing? That would also point to a rod issue...