How reasonable long-term investments in altcoins are can only be said in relation to a specific altcoin. Some live on for a couple of months on the strength, and are suitable exclusively for short-term trading, on which you can make great money if you have time, or lose everything. It all depends on luck. And they are in the majority. But there are also those in which I invest now, and I expect growth by the summer. It all depends on the development of the project.