I can guarantee you no apps will drop their prices 30%. When Epic pulled their stunt[0], 1000 v-bucks that normally costed $10 were only discounted to $8. They still pocketed $1, maybe ~=$0.68 after CC processing fees.
Of course prices won’t drop because price is based on what people are willing to pay. However the actual creator will have up to 30% more funding instead of a rent seeker, which means the creator will have more margin to increase quality, which benefits the consumer.