I don't collect them either but I know they tend to be worth more than 'real' machines these days. My GF used to have a collectables stall and toys were always worth more than practical things, due to the sentimentality factor: You'd always hear things like "Oh, I used to have that" there. Toys remind us of the good times of being a kid, so folks tend to value them more than more functional items. A great investment.
My hypothesis anyway
