Well, altcoins are being developed on various native blockchain like ethereum, neo, stratis, nem etc. As these native blockchain have limitations, altcoins built on top of that appear to have limitations.
The first major reason can be adoption.
If you have mistakenly sent your altcoins to other address than recipient, your sent altcoins are lost. There is no way to reverse back that transaction.
Volatility of altcoins is the most important factor behind poor adoption of altcoins.
I suppose you are right about the addresses as well as volatility. However, if you send a letter with some cash to the wrong address, you will probably lose them as well. And does it really happen every time with cryptos? I mean, if you misspell something from the address and there's no address with the code such as you wrote then they disappear? Well, anyway, as for volatility, it is both attracting and shocking people. Generally, people prefer stability, but technically there's no stability, because people keep selling and buying coins, trying to get profit. In this sense, there's also demand for volatility.
As for adoption, I think it is not a disadvantage of cryptocurrencies, but rather is something that they lack temporarily.
I think that the worst thing about altcoins is that there are too many of them, while humanity need a lot fewer than what there already is. This means that the market will inevitably lose funds, since lots of coins just won't make it with time.
