Currently all the new ICO are trying to develop platforms with different use case than Bitcoin, not similar at all, why people keep calling them altcoins although they are not alternative?
Well altcoins somehow are improved in terms of hashing algorithims or speed of transactions, and some altcoins innovate by experimenting with features Bitcoin does not offer.
Altcoins are referred to as Bitcoin alternatives because, at least to some extent, most altcoins either replace or improve at least one Bitcoin component, that is why it's an alternative.