Yes, we all joke about blaming Alaphilippe, but I think being without a team was more important.
As soon as Alaphilippe attacked, he came out to make a statement and prevent further attacks. If he hadn't come out, attacks could have continued, and he'd have to control them alone.
It reminded me of Zurich. Tratnik said the attack wasn't planned so early, but Pogacar was left without teammates 100 km from the finish, and there were entire teams like Belgium. Being without a team, he preferred to attack because later on he'd be alone against Belgium. The lack of earpieces makes the chase difficult.
That day, if he had waited, he might not have won, not because he wasn't physically strong, but Belgium was too powerful, and with that attack and no direct communication, he made everyone nervous, and the chase was an unorganized disaster.