Because if you integrate with Apple Pay or Google Wallet then iOS or Android become the platform that delivers tailored applications, not your "everything app". Almost like that is exactly how it currently works in much of the world.
You are arguing in the wrong direction. You think I am arguing that supporting payments is a compelling feature for get customers. So, logically, you just need to add the ability to do payments in some way. My argument is actually that a robust payments platform is the moat needed to prevent your "everything" app from fragmenting by preventing your users from going around or under you. A lower level platform that provides a low friction means of payments for delivered services undercuts the coherency of the higher level platform since applications can be delivered around you.
So your examples actually support my argument. Payment platforms like Apple Pay and Google Wallet attached to their service delivery platforms, the app stores + OS, make it hard to lock people into "everything" apps because the OS is the "everything" app. Efficient inter-account transfers prevent "everything" apps from locking users into their payment ecosystem. If you do not have the payment moat, you are left with actually competing on features and delivery of services which is really hard to do across "everything", so you are better off focusing instead of trying to make a "everything" app.
You are arguing in the wrong direction. You think I am arguing that supporting payments is a compelling feature for get customers. So, logically, you just need to add the ability to do payments in some way. My argument is actually that a robust payments platform is the moat needed to prevent your "everything" app from fragmenting by preventing your users from going around or under you. A lower level platform that provides a low friction means of payments for delivered services undercuts the coherency of the higher level platform since applications can be delivered around you.
So your examples actually support my argument. Payment platforms like Apple Pay and Google Wallet attached to their service delivery platforms, the app stores + OS, make it hard to lock people into "everything" apps because the OS is the "everything" app. Efficient inter-account transfers prevent "everything" apps from locking users into their payment ecosystem. If you do not have the payment moat, you are left with actually competing on features and delivery of services which is really hard to do across "everything", so you are better off focusing instead of trying to make a "everything" app.