That is because you are trying to play it like a mobile game. You should stay on the base screen most of the time, focus on expanding and only go to the map when you have an opening.
You also have to go on the map to check and make sure you don't have lockdowns*, because those will (1) make you lose your current scheme and (2) contribute a significant amount of threat making you more likely to get attacked (on the higher difficulties, lockdowns are pretty fatal).
Additionally, in the game, your two biggest concerns are (1) Heat/Threat and (2) Gold. Your primary way of dealing with both of those things in the world map, which is poorly implemented (many, many people are critical of it in both negative AND positive reviews of EG2).
So yes, everyone is spending 80% of their
time in the base, Doomsought, because its way more fun. But a lot of the most important stuff in the game is happening on the world map, because that's where 80%+ of your income is coming from (including pretty much all the income you're using to expand) and that's where all the events that will contribute to a potential invasion will happen.
* There's also very short events that pop up... Each mission has a timer for how long it will be available, and occasionally, special missions pop up that give you the opportunity to sabotage or postpone a Named Agents attack on your base; those are pretty important and another thing to check for.
My point is that I believe the map is both (1) a large and critical part of the game experience and (2) poorly implemented.