I’m not an Oilers fan and only addressing an opinion.
Oilers have made plenty of dumb decisions with picks, trades and management of players.
There is guarantee the Oilers would have drafted Barzal. There are too many variables such as size, teammates and attitude. I remembered predraft interviews, he was arrogant and acted entitled which led to the dramatic drop in his draft positioning. You can’t blame the Oilers when 15 other picks missed as well. Scouting has also been terrible and can’t remember a pick beyond the 1st round reaching the NHL the last 10 years.
Barzal joining the Oilers could have been smothered by the much larger and tougher forwards of the west. He plays half his games against easier competitors that allows him more freedom to skate. This would wear down rookies over a long season for smallish Forwards. Consider early scoring leaders led the league by a large margin have faded: Keller, Connor and Kerfoot.
Another consideration is his teammates and excellent wingers, Barzal has Eberle/Beauvillier (interestingly directly/indirectly from Oilers) is an area the Oilers lack.
Attitude. McDavid rightlfully is the leader of the team. Hall was dumped below value to ensure the leadership transition is smoothly complete. Barzal will just create another problem.
Oilers needs better management and scouting.