Lowering prices probably would increase sales, but the problem is that is might also lower net profit which is the thing you actually care about. If you're a SaaS app charging $6/mo and you have a 100k MAUs then congrats $600k gross revenue per month! You lower prices to $4/mo, your users rejoice, and your sales and marketing find all the people who wouldn't buy in at $6 but would at $4 which happens to be 25k new users -- 25% growth! Amazing! Pop the Champagne! But now your gross revenue is $500k and you have more users to support.
But we weren't talking of just changing the price and keeping everything else the same. We were talking of not having to pay Apple, and passing the savings along to the consumer. With your numbers, the revenue was not 600k/month to start with. Apple was taking 180k of that, leaving you with 420k/month. So you getting 500k and Apple getting nothing sounds like a pretty good deal.
