Bitcoin have future thats for sure. I do believe that there will be some alts standing still not just LTC and ETH but these as well: DASH, DOGE, XMR, ZCASH
There will be more of them. But the point is and will stay prob most of the alts will exist in the future for the people to gamble upon, to create fake value. We all know that most of them were made for profit and nothing else.
Yes altcoin have future for sure there are a lot of altcoins that has good fundamentals and has been there in the market for a long time. Ethereum is the most common example of great altcoin that has future from fundamentals to investors to players it is well played coin even if its a hype sometime you will never know how far this could go but in the end it has a future.
Indeed, I do believe also that even altcoins have a future. In fact there's a lot of coins who have a responsible developers that make it creditable. Yet, some of them has been in the market for a long time and the proof is Eth which is one of the most popular and largest coin existed aside from bitcoin.