Interesting conversation.
But me thinks we are missing something. In Kenya investing in real estate is not just a question of costs and returns.
In a society like ours, with no social safety net to speak of, real estate is about security and peace of mind. This applies even when the mjengo is done with an eye on rental income. It is not without good reason that many people will call their construction project 'my pension plan.'
When you factor in such intangible considerations a pure calculation of return on investment (for a product that many Kenyans will never sell anyway) is likely to lead you to the wrong conclusions.
Plus real estate investment in Kenya is a fantastically lucrative business, even by World standards. If you don't believe me, ask one
Mukesh Ambani. "The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth." (Niels Bohr)