I really think we're heading towards a one-world currency. Nearly all major international banks are ingraining blockchain tech and cryptocurrencies into their business models, including globalist foundation banks like Goldman Sachs, which refer to it as the "new technology of trust."
I hope so, but to be honest I don't think the world is ready for a single currency, simply because not all countries have heard of cryptocurrency, let alone have internet connections. But I believe that more and more people will start using it in the future, just not sure if becoming "one-world currency" is where crypto is heading.
Cryptolaboratory opinion:
In not so far future will stay 10-20 worlds cryptocurrency. It maybe will be Bitcoin(different fork variation), maybe Ehtereum(different fork variation), maybe EOS. We don't know, but that will be.
So, too will stay different variation of blockchains for different purposes, but also we think it will stay privacy in future variation of commerce corporation.
It was very interesting to read your post. Probably, the number of the cryptocurrencies will be sufficiently cut in the future as you say. However, I think, more than 50 altcoins will exist.