I was lucky, I did see them new, visited the dealerships often. I was a total geek
Yes, the toners and chemical make-up are very different now, and it's very time-consuming & difficult to get an accurate match.
It depends on the paint mfr's library of toners, and sometimes you have to start with a more modern color and mess with the formula.
My current Q1 car took about 6 spray-out samples. Used Spies-Hecker BC/CC on it.