So the servers of Pokemon Go are unstable.
The game crashes frequently.
The game loses it synch with the server often.
Usually if companies release an online game and this happens they put a full stop on acquiring new users, even close down the registration and fix things first. As users are the most important thing you have. They are your customers.
Not so Niantic. Despite servers being overloaded they add country by country putting even more load on the servers - annoying most players.
I asked myself why. Niantic isn't stupid. So the only explanation I have is they want to increase the value of their company before users get bored with the game and numbers stabilize. To explain (easy model): a company's evaluation is usually based on yearly revenue times a multiplier, like 3. So if you do 100 million a year you are worth 300 million.
So Niantic adds countries to raise revenue so their evaluation gets higher and higher. I think there is someone negotiating with them to buy - and they release country by country to put pressure on them to close as otherwise they get more expensive over time. Nintendo surely is interested. Now they can afford it too - easily.