The first to believe in Muhammad's mission were his wife Khadijah and her uncle Waraqa bin Nawfal.
Very few among the men of substance of the Quraysh were willing to follow him except Abu Bakr,Umar b al Khattab, Uthman b Affan, Hamza b Abd al Muttalib, Abd al Rahman b Awf and Sa'ad b Abi Waqqas.
Muhammad'sABYSMAL failure in his attempts to convince his own tribe of Quraysh of his message and his mission, is reflected in the fact, thatless than 100 people in 13 years -mostly from among either the poor or from among the slaves - accepted his message and hence were of little influence or prestige in Meccan society.
The simple fact as to why his tribe of Quraysh could not and would not follow his new 'religion' was because it would have deprived them of their status as guardians of the Ka'ba and hence the loss of their wealth and prestige.
Thus, one of the most fundamental acts of Muhammad after the conquest of Meccawas to keep its centrality, traditions and fetishes intact while eliminating all its idols.
Hence Allah became the supreme god of the Ka'ba without the other 360 gods and goddesses. The Quraysh, thus retained their power and wealth and were more than happy to accept 'Islam' and Muhammad as the messenger of Allah.
*** From the Quranic 'scriptural' point of view, Muhammad, with a single stoke, TRANSFORMED and METAMORPHOSEDALLAH, the supreme rock god of the Ka'ba residing in the BLACK STONE, into the God of Israel and Jesus ***