There are now (as of July 2019) well over 2 thousand different cryptos and many remain forever meaningless and quite a few are experiencing a boom and then disappear again into insignificance. But the good coins will prevail and that are relatively few.
There are certainly some helpless cryptos today that will make it to the top. However, it is very difficult to fish them out of the big crypto sea. However, the current Top 20 cryptos have generally proven over a long period of time that they can survive in the market.
Investing in the top cryptos is therefore the safest option. However, one should keep in mind that behind top cryptos only people are stuck and people can make mistakes. Therefore, even a top crypto can disappear into insignificance. For this reason, it is discouraged to invest all capital in just one or a few cryptos. Instead, each crypto portfolio should contain several top cryptos.