Actually, they mainly solve third world problems so far. As data storage, they are relatively inefficient compared to regular servers.
- They facilitate fast and cheap transactions. However, I can send any amout to anybody within the EU, knowing only the person's phone number. For free, instantly. I can do so to a bunch of non-EU contries the same way.
- Cryptocurrencies store value. However, the high volatility makes them too risky for short term savings ("Let's save money for our summer vacation in Bitcoin" is definitely not the safest family policy).
- It is immutable. However, developed countries don't really face issues with freedom of speech and censorship, with a possible exception of the US (see).
Two years ago, we went to Cyprus and crossed the UN buffer zone (it felt like crossing the Berlin Wall a bit, see) dividing the country into southern Greek part, an EU member state, and the northern separatist Turkish state, which is not recognized by any other country but Turkey.
The Turkish region is extremely poor compared to the other one, and there are many crypto stores, see this post for further details. The Greek region lacks demand for such venues.
My two cents. Or my two satoshis? ;)
The fact is, people, companies and nations are using blockchain in the EU, in the US and in developing nations too. The question of one blockchain to rule them all (which is my point) I think is flawed. Blockchains will work together.