I don't think "raw, unfettered capitalism" and unions are orthogonal.

In a vacuum, no. If the most profitable approach means involves maintaining an "all star" cast to keep the best team happy, then everything works out. That's the athlete/celebrity model.

But current dynamics has games divorced from quality to generate the most profit, and companies work to minimize expenses instead, via the assembly line approach. Devaluing labor to maximize money makes unions inevitable.