I know, sorry that was a bit cold but if you have a pair of 85s sole, compare with a 2019 version, it's about a half size difference at a minimum. There's literally articles that got published about this...
The arch thing only works in the 80s when obesity was not a big contributor of death in America. The midsoles were a lot more narrow and helped give that arched look. It's wider now to accommodate a wider range of feet. Similar to off the rack boxy suits vs. tailored.
Another thing they can do...