And it is worth remembering that Melchizedek came out to Abram, not the other way around. Also, there is further discussion here and here.
That makes sense because as a king an priest and if he knew Abram from his childhood, he knew Abram had the promise of God to be the father of a great nation. The Jebusites(dont know if they were jebusites then they were in time of David) in Jerusalem were small potatoes compared to what was to become.
David paid cash for Arunahs threshing floor which became sight for the Temple so there is a three thousand year old deed of trust....if one were to do a title search guess who is trespassing in that land? it’s not the Jews...just saying
LEX