it just seems nokia tops the depreciation chart but the way i look at it, its just similar to all other leading brands.
example s.e. ni ryan bought 4 moths earlier than your friends n80.
back then it was around 35k (some shops offering it as high as 45k) if im not mistaken...now its only 13-14k.
and thats without a high end replacment to the p series.
nokia just seems to depreciate more because it sell out faster thus new price all the time in smaller amount but constant week per week as distributors and suppliers get new stocks.
where as other brands sell slower thus new price comes couple weeks later but in bigger amounts.
distributors/suppliers order in bulk. only when those stocks are sold out do they get new stocks and only then can they adjust the price. am i making sense?
look at it this way.
if nokia model A and s.e. model B and samsung model C and moto model D comes out with a unit worth 20k in april.
by june A would be 18k(new batch new price), B 20k, C 20k, D 20k.
by july or august A would be 16, B 16k, C 16k, D 16k.
so given enough time for the other brands to catch up, depreciation wise, they would catch up more or less
besides, its easier and faster to re-sell a nokia that the other brands...specially in the lowend to mid range...