The chemistry with a quarterback and a wide receiver doesn’t just happen overnight. It takes thousands of reps and years of work together to develop a mind meld between the passer and the pass catcher, developing a sort of telepathy to be on the same page regarding timing, ball placement, and various other factors when it comes to completing passes in all quadrants of the field.
We’ve seen it happen with the greats like Joe Montana and Jerry Rice or Peyton Manning and Marvin Harrison where the two were so in-sync that the QB knew exactly where his receiver would be during a route and where exactly he wanted the ball for his receiver to have the best chance to come down with it in coverage.