I know only a very little about bikes, but what I have seen is that Sportsters depreciate massively in market value, as they are far less desirable than the longer wheelbase ones. I’ve seen say 10-year old Sportsters selling for 1/3rd of what the equivalent-age longer ones sell for. So a used one might be a much smarter buy.
Ummmm.....maybe that’s because the Sportster only went for 1/3 of what the big twin went for in the first place? For what it’s worth, I’ve never sold a Harley that I didn’t make money on. Well, I did put over 200,000 miles on one, so if you can’t count the cost of the 2nd engine, I might have lost money.