>>17783740The general region of Arabia had various groups of Christians, Jews, other monotheists, and likely some pagans during the lifetime of the prophet Muhammad. He was a merchant before his prophethood, and he came into much contact with various monotheists such as Christians and Jews, who would influence him the most. Some surahs in the Quran are literally just stories taken from Christian legends and literature, a lot not even from the bible (for example surah Al-Kahf).
It's really no surprise that when he started to make his own belief system, Muhammad took the Jesus figure from Christianity as Jesus was pretty popular at the time. Monotheism also became firmly dominant in Arabia for quite a while now as indicated by rock inscriptions that over time pray less and less to gods other than Allah (The God). It could be an evolution of Arabian paganism that adapted to the Christians and Jews, but we really don't know why we see less presence of other gods. This context of increasing monotheism might have influenced Muhammad into styling Jesus as a non-divine prophet. Or maybe there were some who believed in Jesus to be a messiah but not divine and later influenced Muhammad to agree.