Macs generally have less depreciation than Windows PCs. However they are both consumer electronic goods, in a rapidly evolving technology market. Do not expect anything amazing, be happy with 50% in 3 years time. If you brought it for $1400, and expected to sell a 3 year old computer for $1000, why wouldn't anyone just pay $400 for a brand new up to date model? Base models are worth less but cost less, there is no rarity as they sell container loads daily, and the tech is generally obsolete very quickly. So the only people buying them tend to be bargain hunters, who inherently are looking to pay cheap.
FWIW, never buy something to use with the intention of reselling it, you'll hinder your purchase and weaken your experience for the duration you own it. Get the thing you want, and enjoy it.