Yes, but that could still generate in a positive result for the new font that wouldn't be seen in the real world over a long period of time. The simple fact that the new font is new could result in an improvement that wouldn't necessary last in the real world. Hence why the font is being retired after a decade of experience and data in a proper situation.

A/B testing is notoriously hard to do well, especially if you're comparing something the user already knows well with something different. Controlling for familiarity is pretty much impossible.