Always it is impossible to predict the future of altcoins, but at the same time block chain they were designed for continue to be used and developed, then the altcoins will continue in future also. Altcoins have a smaller investment when compared to Bitcoin. Many governments around the world are beginning to be legal to cryptocurrencies.
I don't know what you are talking about, I've not heard of any government legalizing Bitcoin lately, but more of them are trying to either ban it or regulate it since they know they can't control it and they find it a threat to their financial institutions. They even ban or regulate the platforms running within their countries that use cryptocurrencies.
You are right that it is not possible to predict the future, whether it's about Bitcoin or altcoins, you can never know exactly what will happen in the future, but based on the potential and what happened in the past, you can make near possible predictions sometimes.