Because it's not worth it, and will favor a certain type of apps - weather app (like this one https://www.ventusky.com/ https://www.ventusky.com/), you check i

Because it's not worth it, and will favor a certain type of apps - weather app (like this one https://www.ventusky.com/ https://www.ventusky.com/), you check it maybe 2-3 times a day - news reader, you check it few hours a day why should the news reader generate more revenue than the weather app that needs licences to various weather channels only because the news app is open for longer?