Think about this way: both companies are bidding on the same keywords. One party (the developer) collects either $97 if the consumer signs up on their website directly or $70 if the consumer downloads the app and signs up via the app store. The other party (apple) collects only $30 (at a maximum) if they drive the user to sign up via the app store (30% of a $100 LTV).

If they’re both bidding on the same keywords, which they are, then the price of the keywords is the same to each of them. It’s an auction, so whoever bids the most will win the auction. The developer can spend up to $97 to bid on that keyword and still be profitable or at worst break even, while apple can only spend up to $30 to stay profitable or break even. So if Apple is winning auctions, it means they’re spending more than the developer, despite having less than half the purchasing power of the developer. So they’re spending negatively almost no matter what.