Yes, we usually see new projects flocking in when the market is bullish and, they tend to decrease eventually when the market starts to become bearish again.
Too many new projects are being said that they've got the potential but how many actually of them reach the climax and are liked by the majority of investors?
It depends on the personality of each person, if you are the type of person who likes to be safe then you don't need to care about new projects just focus on holding the top projects. If you are a risk-taker, love to explore new things and are willing to take all risks, new projects are the choice.
We have hundreds of new projects every day and choosing a hidden gem is hard, it requires a lot of knowledge and experience and it's not for the masses.
Yes, you can stay with holding bitcoin and other common altcoins like ETH. That's all you need to do if you don't want to take risky investments by taking more altcoins in your stash.
There's really no need for you to be that type of investor that you'll hit every single new project that you see. It makes no sense because it's not that really needed at all.