Before Bitcoin all altcoins were just considered to be shitcoins, which i would have agreed as most were just clones of Bitcoins code and had no use case.

Looking at the history of coinmarketcap in 2015 July 26 there were a lot of useless altcoins and many of them didn't survive to today. Ethereum was considered to be another useless shitcoin and it did have a lot of problems at launch, but now it has major usability for creating ERC20 tokens, which coinmarket cap is filled with (Ethereum was created in 2015 July 30, so the coinmarketcap link is about the day Ethereum launched).

Now if you go to coinmarketcap you can see coins that are actually real, with different use cases (or they try to be). It isn't just 5 coins like before, but probably a few hundred of them which secured partnerships and are aiming to provide for users a new way of payment/utility/securities. Businesses see that there is big potential with blockchain and they want to be part of this new technology.

In 2017 December the altcoin bullrun happened because people found out that there were basically cryptocurrency penny stocks, which meant high risk, but very high reward and started pouring their Bitcoin profits onto ICOs and altcoins. That is why when Bitcoin went down, all altcoins suffered the same fate and were overall very risky. Today altcoins seem to be more resistant, with introduction of upcoming FIAT pairing and numerous other feats. The small cap projects are growing and big players with $$$ are noticing this. Altcoins will start being noticeable to the public and prices will obviously increase, while Bitcoin may fade away because of its old technology and inability to update.

In the end the word altcoins will slowly phase out, because there won't be a huge gap between big boys like Bitcoin, Ethereum, Litecoin compared to NEO, Vechain, IOTA since like before, Ethereum being a shitcoin in 2015, now can't be considered an altcoin. The word "altcoin" may as well be defined as - "not bitcoin".

TL;DR: Just like Ethereum was considered useless at launch, so are most small cap coins, but after a while adoption will rise and more legitimate coins will fill the crypto landscape.