That statement contradicts itself. The issue is not advertising, but when the game advertised the population skyrocketed.
The many issues that have been brought up in this thread are all part of retaining players after they join/come back. But without advertising those players won't join/come back in the first place. Nor will it attract potential new developers that may be interested joining in the project but haven't heard of it.
The developers could fix all the problems with this game but if no new blood is brought in the population will naturally stagnate and decline. The applies to developers and players.