I own 4 apps on the app store and get about 10k views or so a day but I don't currently earn anything decent.
It takes me about 4-6 months to earn $100 off my apps, I have only one bottom banner ad and one interstitial ad. I did this to not annoy my users too much
But I think it depends on your app category and CPM/CPC for your country.
My country has a lower average CPC so this also affects my income. Some people earn a decent living from Admob and some do not.
Games especially earn a lot because they can use more ad types like reward ads which have higher pay.
It's a decision you have to make yourself. You can also put ads on the free version of the ads and remove it if the user pays or you can just put a price straight forward on it.
The only disadvantage of putting a price is you get lesser downloads/users but you get your money immediately.
In my case, students pay to access the app but I kept little ads there so that way I earn passively from free users(restricted features) and I earn a bit from payments from the students.
Just my thoughts