Ethiopian Airlines tickets seem to always have the same price regardless of the proximity of the date?

UPDATE: Ethiopian Airlines indeed offers a currently 66% discount on domestic flights, if you're an Ethiopian resident, or if you fly into/out of Ethiopian with Ethiopian Airlines. When trying to book a domestic flight on the official website, you'll be asked if you satisfy one of the above conditions, and a discount will be applied automatically. This practice does seem a bit protectionist/monopolistic though, as the answer pointed out.

I am planning a trip to Ethiopia. It seems that to travel between Ethiopian cities, the easiest way is to take flights operated by Ethiopian Airlines.

Normally for trips in Europe/America etc., you would book flight tickets well in advance in order to have the best prices.

However, on the official website of Ethiopian Airlines, I was surprised to see that the ticket price seems to be exactly the same for planes departing tomorrow, as well as for planes departing five months later.

Also, the ticket prices don't seem exactly cheap. They're certainly much more expensive than many European flights.

Is this situation normal? Or is there some place where I can find cheaper tickets for future dates? This is something I've never seen with any other airline.

If the price is the same anyways, I might just as well buy them much later, in order to keep my schedule flexible.