Regulators are the reason for this.
This article conveniently omits the reason for the gigantic A-pillars - Other safety regulations that enforce a certain coverage of airbags for the passengers. We can't magically regulate this one away. These kinds of higher order consequences tend to be a really painful, gradual realization.
I would gladly purchase a new vehicle with zero airbags in it if I were allowed to. Especially if the tradeoff is a 50% buff to visibility in the corners. I would also happily sign a form that locks up my vehicle's title for all eternity and prohibits any form of resale to satisfy the safety-at-all-costs extremists who caused this mess in the first place.