Have you tried (risked) operating one with PSEN shorted to the ground? Maybe the power consumption is excessive, the chip gets warm but still nothing gets damaged and you really can leave the PSEN pin shorted to ground, and they just meant exactly what they said?
The fact that one chip manages to survive (maybe with a shorter lifespan) does not prove that any chip will.

I detest this "if it works, it is ok" attitude.

Successful testing does not prove the abscence of bugs, it proves the abscence of knoen bugs.

Erik