Imagine a scenario when all mobile phone companies finally decided to add a custom default bitcoin wallet to all of their devices as factory app. I believe that will further increase the adoption of bitcoin
No, it is not a great idea. But they may initiate such kind of idea in future when bitcoin adoption is in mainstream because they can take the custody of the user's bitcoins and cryptos with the wallet they installed and it is also going to be a wallet with full of ads which no one ever wanted to install.