Technically speaking, an altcoin has value for the same reason everything else has value people are willing to assign that much value to the object.
If the dev and community is focus on there project altcoins getting high the target of value
Every project has a target and goal to achieve.
I agree, as long as they focus on basic goals by building a planned marketing. There coins will be still valuable.
Although not all altcoins projects are successful, but at least they remain on target and development. I am sure they will still be successful in the future.