I'll just add a last word on the whole "Audi 80 on summers vs FWD on winters" story as it may be a bit funny but can't be used to draw conclusions at least not by anyone with a half-decent understanding/experience of driving on proper snow.
As I said earlier, it's perfectly possible to spin the wheels on a FWD with winters if you want to. It's even possible on a AWD with winters. There are several variables in that story that we don't know that could provide an explanation. What seems more probable to me is that the cars were parked on a very slippery surface. Setting off at an icy uphill can be quite tricky even with winters. At the French Alps, I was driving my FWD with winters fine through 1month's hardened accumulated snow, I was even going up and down 10% slopes without any issue ever but just once I parked it on a friend's slightly inclined yard at a time that half-melt snow was re-freezing. Leaving his place afterwards I wasn't able to get going without some pushing. Once going I did again everything without drama but I want to stress that setting off at the wrong combination of conditions can give you trouble even with winters and that is the only situation that AWD would give you some extra help. That does not prove AWD is preferred to winter tires when you have real snow on the road simply because setting off is one thing, but car control while moving is another with no help from AWD. I also have to add that unless your friend had just a very dirty parking area to start from and then everything was rather clean on the road, he should have never set off on a car with summer times if at the same time a car with winters was unable to start, corner or brake safely in the same conditions. This should be common knowledge.
As a bonus, have a look at the following video of testing an EVO and an STI with summers and then with winters:
https://youtu.be/uHKjXfbqc90Based on one random story here and another member's enthusiasm I would expect the outcome to be "who needs winters" or at least "summers work fine for the most part". Well guess what.. I quote the narrator/test-driver:
"(leaving summer tires on) is not something you want to do. This was a base run to see what these cars can do with summers and the answer is they don't do much. Even with AWD they just don't have any grip for accelerating, cornering or stopping" Oops, time for some to give that car seller an angry call I guess... No surprise for the rest of us.
Also, don't forget these two are cars with AWD systems with multiple locking diffs and special modes for optimized torque distribution for all sorts of roads snow included (of-course with the proper tires on), miles ahead in performance from any Haldex clutch system and they miserably fail to be driveable with summer tires as you can see they are all over the place. Still, to this day every forum has their over-enthusiastic R/S3/xDrive owner who will buy none of this and claim his car to have powers that defy simple mechanics and common sense...