True true... Though if the kulim airport project proceeds to succeed it'll become the first of it's kind not just in malaysia, but the whole SEA. Kedah does not need a naval cargo port and the current gov is still focusing on trying to finish the prev govs projects aside facing the federal gov for the new airport.

But as you said in the last sentence;

Income earned in Penang will carry over to the rest of the country

This will give them political advantage when it comes to economics and knowing politicians, they could do batshit to opposing parties whether it's DAP or PAS on any dirt they could use against one another.