When Obi Wan takes Luke to Mos Eisley, what if he’s actually looking for a specific pilot? After all, it’s a wretched hive of scum and villainy, Obi Wan would be smart to find a pilot he could trust. Who else would he turn to but someone sympathetic to the Jedi, who fought alongside the Republic during the Clone Wars and whom Yoda considered a great friend?
He was specifically looking for Chewbacca. Han just happened to be the obnoxious dead weight.