Well, how many first round worthy WRs drop to the bottom of the round, where the Bills pick? They're generally gone by pick 20 or so, as bad teams ahead of the Bills scoup them up--pushing other positions down the board for Beane.
They've used FA for WR2 and WR3, getting vets who could help Josh grow and develop. With the salary cap constraints that kick in next year, I suspect 2023 is the year they work the draft to land cost-controlled WRs to bolster the offense.