This game has been around long enough for EA to have added an invite feature for alliances. What is the deal? It’s seems as though that everything EA has had their hands on the last few years is not very good, the quality is definitely lacking.
The lack of such very basic features means that whoever set the scope for this project was not clever. A clever person would have known that inviting a player to an alliance absolutely is a much-needed feature, and thus would have included it.
Since July 2019, no new features have been added to the game. It is therefore likely that things will stay like this.
