I agree with you, its better to be strong in one asset (bitcoin), than to have so many weak investments. If I have build my bitcoin portfolio at least to maybe up to 5 years of accumulation I can now start think of diversifying but this might be too early in some case especially when i have not accumulated enough bitcoin, I always wanted to have at least 10 bitcoin before I considered any other investment, but you have also told me I should be prepared for a case where my investment doesn't give any return, and till now I've not actually understood the lesson you are trying to give me in respect to this, I'm building up myself in terms of cash too and I'm still consistent with buying bitcoin with DCA.
I suggest you to focus on Bitcoin for now instead of having a lot of investments. Once you can position yourself well in Bitcoin investment, you can start diversifying. But this diversification in altcoins may be more confusing because there are so many altcoins that we don't know which altcoins can rise. Moreover, it looks like altcoin season is about to start so if you have difficulty choosing an altcoin, you might have difficulty making a profit.
But if you focus on accumulating Bitcoin, your chance of making a profit over the next 5 years could be greater. Moreover, in 4 years there will be another halving and maybe there will be another new ATH for Bitcoin. By preparing a Bitcoin portfolio, at least you have saved in the form of Bitcoin from now on which can provide benefits in the future.
But please remember that when investing, whatever it is, whether in Bitcoin or anything else, you have to use the money you can afford so that it doesn't interfere with you meeting your daily needs because that's what's more important. Investing is highly recommended but you also have to think about meeting your daily needs.
Personally, and in my own opinion, we plebs shouldn't treat our little/limited capital like it's Warren Buffett's billions that needs to be "diversified". It will slow down our ROI plus it's probably not needed. Diversification is made to protect capital and control risks because their billions has more to lose in every small market move. For us plebs, if we truly want to make life-changing profit, then, only my personal opinion, we should take more risks and concentrate capital to just one investment that we can have strong conviction to HODL long term. If you ask me, it's a golden opportunity to buy and HODL Bitcoin.
Well if they only have small capital to used then I think they should not focus to hold since there's nothing gonna happen with them if they only decide to hold the small amount of money since if they calculate the profit they get for long term for sure they can only get less that's why instead of focusing on one thing much really better if they split their investment to half and use the 50% for trying to make your money grow by either you trade it or use it on other options that you think can give you a decent profit. The half is automatically for HODL. For sure people will see the best result if they try to find ways to make their bitcoin grow since this can give much better result especially if they are wise taking those good investment online.
I also know its hard to achieve to get good profits or the passive ones but if we gain a lot of experience especially dealing with those risk for sure we can figure out what's bad and good investment for us.