Someone who isn't a car lover is the kind who would deny others transportation that they enjoy, because they don't even think about transportation the way someone who actually likes cars would. They think about cars as rational purchases, to fill a need, and don't recognize that almost the entirety of car culture is counter to that assumption.

edit: TL;DR can stop there

I could be wrong, but someone who would buy this era A4 is very likely someone who wanted one specifically for what this model offered, but didn't have one when they were new. Perhaps the next newer, or multiple generations between then and now do not fit their desire in the same way (eg. the further you go passed this model to current, the more corruption from non-Teutonic influence creeps into the design).

Thinking about cars in terms of return on investment is like thinking someone should only collect comics that have a chance to appreciate or fit someone else's idea of significant, not what someone likes. Those people exist, like those sad individuals who collect action figures but never open the packaging, etc.

A 1957 Chevy would be a good "investment" but it would be a worse daily driver and to those who don't find any appeal or fetishistic draw to the car, it would simply be an old, uncomfortable car with terrible handling, no brakes, anemic acceleration and that would likely kill them in a serious collision. Same with a 1965 Mustang. Or almost any actual collectable car that makes sense on a spreadsheet.

Were I wealthy enough to have a large stable of cars few of my choices would make sense to anyone else besides those who have specific interests in specific cars that are interesting and desirable for not other reason than they are that model from that year, and this has nothing to do with what Kelly's Blue Book thinks, or your buddy, or some auction. There would be a niche of people who would nod their head knowingly at each choice, but I wouldn't expect there to necessarily be a lot of overlap between them.

Anyone familiar with the yearly H2Oi car meet knows that this era of A4 is still very desirable to those that love them and as a platform they offer a lot to the enthusiast.