Why most of the contracting companies prefers to promote Business Development persons as CEO or President ? Why not from the technical team ?

as they are most knowledgeable than the junior managers. 

Experienced Business Development Managers' are capable of Developing strategic plans that are in line with the Objectives set out for the organization, they possess high degree of commercial sense that is very essential to promote and streamline revenues thereby helpful to maintain and improve profitability. They are capable and experienced in implementing varied business concepts like the requirements of work efficiency, the importance of quality and timely service--they have capabilities to plan, develop and implement strategies for generating resource requirements---they can find out and implement various amalgamation options for the business---Whereas the technical teams are experts with more on Technical aspects mainly--For negotiation skills BDOs can acquire technical knowledge very quickly and without much efforts.

It seems to be here in my country same same but there's some exceptions for that rule.

Agree with the well  developed answer of Mr Ventikaraman.

AGREE WITH MR. VENKITARAMAN

Because Business Development persons have overview of things.

To develop the business with higher understanding to business and development then the technical background.

main cause of bread and butter....no business no technical team...

Experienced Business Development Managers' are capable of Developing strategic plans