What's an ideal IQ?
I'd assume it is an IQ that people would consider to indicate they're as smart as they think they are.
What does an estimated IQ even mean? Is this estimated according to an average of contemporary intelligence levels, or the average intelligence at the time? Because we're a lot smarter than we were a century ago.
I suspect the estimated IQs are actually a load of rubbish. Academics tend not to have substantially higher IQs than engineers, legal experts, or medical professionals. There's a certain correlation between IQ and academic success but since there's a spread of 30 or so points between the second and fourth quartile I doubt you can really estimate with any sort of accuracy.
It is really no different than instances of "you have 1 message(s) waiting". Back in the day, when bytes and cycles really counted, saving the execution of a statement, and the program code space associated with checking for 1 or more-than-1 was understandable, maybe even desirable, but now? The only reason is a lazy programmer.
I really think even then it was programmer laziness. It's still only a few bytes to do the check, and programmers didn't need to be that frugal. The only time when this would have made a difference was when memory was in such short supply that you'd consider rephrasing the message itself to take up fewer bytes.
Real Programmers don't eat quiche. They eat Twinkies and Szechwan food.