The argument that corporate sponsorship helps to keep concert-ticket costs down is specious.
Without corporate sponsorship, ticket prices could stay the same or even go down--if the venues, promoters, musicians, et al., accepted smaller profits.
I do not say they should be obligated to do so. They can charge whatever they like. It is up to the consumer to decide if the goods are worth the price; just as it is up to the consumer (a.k.a. the people) to decide if the politics of a musical act, or a corporation, are worthy of support.