The difference is in terms of stability. Most popular capitalized projects already have a solid foundation and backing by many players in the crypto industry. Some even have other projects built using their blockchain. It's not difficult to see why most investors would rather put their money in popular crypto coins than the newer altcoins. During the bear market when the prices of these capitalized coins go down, the investors are always confident that when the bull run comes back, the price will go back up and possibly attain a new all time high. Same cannot be said for new coins as the risks are many and most of them do not get back up when the prices are up after a bear market.