Would it solve the problem if the funds allowed their owners to vote on each company's issues? E.g. Your ETF directs you to a website where you can vote your whole shares on any and all corporate events, and if you don't vote the fund cannot vote for you?
This might increase costs less than expected if centralized service vendors were used to match ownership shares with voting rights. However, because very few shares would ever vote (imagine the workload for VTI owners), it would concentrate power in the hands of individual shareholders and activists.