Year of manufacturing says nothing; you can have two different gens manufactured in the same year, one for lower price tier and the other for the higher one. Just like Apple still produces older iPhones, same thing.

Instead, you have designations like "Intel Core i7 8565U Whiskey Lake" or "Intel Core i7 10510U Comet Lake". The first one is 8th generation (=8xxx), the second one is 10th generation (10xxx, but the 14nm one, not the 10nm "Ice Lake"), and most OEMs do put these into their marketing materials and they are on their respective web shops (these two specifically were copied from two different Thinkpads X1 Carbon models).

That gives you the opposite problem, where someone gets a brand new dual core and is confused by it being slower.

Best is to give them a number that approximately maps to performance.

The "pro" version might be an i8, while the budget version is i3. In a few years time, the pro version will be up to i12 while the budget version is now i8.

You have model numbers for when someone needs to look up some super specific detail.

Right. The issue I have with this is that we have i7 models that are from 5 and 10 years ago with vastly different performance due to their generation. If it was more iterative it would make more sense.