Honestly, the less Apple made apps, the better for the ecosystem and the quality of the apps in general. Apple's recent "sherlocked" apps are not good quality at all, but they make it substantially more difficult for 3rd parties to compete with the now default offerings.
Generally speaking, Apple should be improving and adding to the base operating system all the time, including new apps. It is better for their users including new users if the phone itself is capable of more out of the box.
Where they fall short though, the App Store is right there. There’s almost always a better alternative for those who value having something better.
Not a developer, but I feel like Apple improving the defaults has been good for the ecosystem. The Reminders app is an example of this, because as it has gotten better over the years, the baseline for a good iOS to-do app has been raised, without reducing the market.