<<Google Play Had a Profit of $8.5 Billion in 2019 With Margins of 62 Percent. According to court filings unsealed>>
https://www.thurrott.com/mobile/android/254978/google-play-h...
So, no, with indecent margins like that, you can't justify them using their monopoly to racket app developers with fees that are unrelated to the usage of the service.
Imagine if everyone was doing the same in real life, that would look absurd:
- your power utility provider requiring that you pay to them 10% of your business income because you use electricity somehow and they have costs and need to do profit
- the postal service requiring you to pay 15% of the bills you send by email through their online service or 10% of the bills you send by any other provider just because you benefit from receiving standard letters in your home mailbox. Just because they have costs and they need to do fat profits.
- Ikea forcing you to give them 11% on your business incomes because you use a desk and a chair that you bought there in your office. For the same reasons...