Old coins can still be profitable, they've been replaced by newer coins because most of the new ones have a higher market cap. Just because other coins have a higher market cap it doesn't mean that they're profitable than the lower ranked coins. Always remember that each coin has it's own kind of price movement not all of them have the same gains and losses so the potential to profit from old coins will be there. Last year ripple had the best improvement even though it's market cap is not high as Bitcoin.