I do think the i3/i5/i7/i9 monikers are actually pretty confusing, just speaking as someone who has been using computers much longer than the brand existed. Problem is that a CPU from 2009 is going to be called an “i5” and there are just so many people who say they have an “i5” or “i7” without knowing what generation it is from.
i"X" is the tier, and the number after that hints at generation and rank.
There may be better ways of doing it but it isn't hard to figure out for someone who needs to know.