The classical altcoins do not offer anything relative to Bitcoin, except maybe a different hashing algorithm. An important thing to remember is that there is no long-term market niche for two coins with the same algo. The hashing power of the larger coin is constantly threatening to destroy the smaller one. Even if that does not happen, there are network effects in play that favor the larger coin and suppress the smaller.
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While this (and some other things you say) makes sense and sound solid, there is no guarantee that the future of altcoins will "make sense".
I think we can only say one thing, the altcoin landscape will look very different in time, and no one knows what it will look like.
I think whatever it looks like will be a surprise, and is presently unpredictable.
Peace to all.