How ironic when diversifying your investment is exactly the same reason as what you have in your statement, "not every altcoin in the market is capable of pumping". However there those that are capable of multiplying your capital. None of these coins you are certain with or none of the investors knew what happens with a specific coin. Diversification isn't the problem, choosing the right coin is, that why we need to diversify to try not to miss anything that will pump in the future.
Choosing the right investment opportunity is what people have failed to do and end up getting financially screwed when the chosen investment fails and their money goes down the drain.
It’s always best to spread out your investments and not to dwell on just one source. But what people mainly fail to do whenever choosing through available investments options is their thorough research on their viability.
There are some good alt coins that has shown some promise and made some profit for some people who were willing to take the risk. We shouldn’t also forget that no matter how profitable an investment may seem to be, there’s always a possibility of it failing.