There are too many projects that we don't really need it on blockchain.
Sometimes, I think there is a black swan (Blockchain is useless in real life) lurking around.
You are misusing the term blockchain instead of altcoins/tokens. I agree that we do not need this many altcoins or this many ICOs based on repeating concepts and for repeating purposes. But, it is a free world, we cannot do anything about that. Some Joe is creating a new coin based on blockchain technology by believing into some other Joe will invest into that. Creating and investing here are personal things of two people and it is right as per basic human rights and by decentralization concepts.Sometimes, I think there is a black swan (Blockchain is useless in real life) lurking around.
apart from being used for cryptocurrency and for transaction, there are lots of other things that we can do with blockchain, a lot of them.
The application of blockchain technology for our life's need is unlimited but exact infrastructures needed yet to be developed or invented. But, OP is concerning about numerous useless altcoins but not exactly on blockchain technology. We need blockchain technology for many reasons. Dot 
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