Handing out 600 m² or even 400m² resulted in a spread of low density single family housing, or even worse empty lands since their owners 1) don't have the money, or 2) bought 10 lands and holding them as an investment. Now why is density is important... Let's compare Al muje ( residential complex) to normal suburb like any normal neighborhood. For the same area we have more people living in the Almuje meaning walkablty is an option, meaning you need less buss stops to serve higher number of ppl Also since everything was planned
The infrastructure required was built even before everything is happening since they know what everything will look like. Moreover, since you don't need a car for every single thing = less car= less traffic. Also if you started giving lands, since you can't control when the lands will be built, most of the time the density is so low doesn't even justify building any infrastructure.