Those box sets turned out to appreciate as you could imagine they would being European and limited and Campagnolo, but if you put in the same money in a S&P index fund in 1983, you would have made thrice than buying a Campagnolo box set.
Buying bikes is a lot of fun, but as an investment... maybe used steel on the cheap and refurbishing it. Or something which has been raced by someone famous... maybe. Right now ex pro bikes are discounted compared to new, being used items.