Most Africans especially Nigerians prefer liability to asset. In the journey of becoming a successful being, it is advisable to acquire more assets than liabilities. The questions here is where does 70%- 80% of your income goes? Asset or liability?
I completely disagree with this brazen claim of yours, what statistics or proof do you have to back it up that Africans (Nigerians more specifically like you said) are more concerned about acquiring things that are liabilities to them, than stacking up assets; i can categorically state that it is wholly untrue. You can prolly call it a human trait, but to pinpoint a particular people as doing it more without stats is uncalled for.
Having said that, you quite forget that in most parts of Africa people live below the poverty level, some even earn less than $5 a day, quite a lot of them are basically concerned about what to eat, wear, good water, etc, that they can't even condition their minds to dream of acquiring luxurious items, only the wealthy/rich can afford it there. It is in parts of the world where life is much better, first world countries were people earn a reasonable minimum wage that you could talk about even the middle class citizens leading a somewhat comfortable life.