At a certain point, there may be a need for an investor to delve into something that is certain to provide a faster return, perhaps in a short period of time.
If Bitcoin is not volatile enough to vomit the much needed quick profits, you might consider ponzi schemes that supposedly multiply your capital within few hours.
If you want to diversify your investment when you have already invested in Bîtcoin, buying altcoin is not a good step in diversification because if there is a failure in Bitcoin there will also be a failure in altcoin.
Many people are entangled in the illusion that altcoins is diversification. To me it is just another way of compounding the problem because the risk is exponential; you can lose everything. I consider Bitcoin safer and more reliable
You can diversify your investment in something different from cryptocurrency such as real estate investment or selling a variety of merchandise, so that if one market fails, success in others will reduce the impact of failure.
I agree with you that diversification should be into something else and definitely not altcoins when someone is already invested in Bitcoin.