There are millions of apps. Thousands of new ones get released every day.
I probably use 10 different messaging apps on a weekly basis.
Every car, appliance, city, school, bank, grocery store, airline, festival, celebrity, have their own apps.
I worked in mobile application development for the past 5 years. I know how much it costs to build even the simplest application.
Why are there so many apps? How is this sustainable? Why didn't anyone come up with a better solution? Why is nobody talking about this?
An app allows a company to stick their logo (as an icon) on the customer's phone, where they'll see it constantly. It's a form of advertising.
Having an app on the customer's phone allows a company to track that person and push messages to them.
A business might feel compelled to have an app because their competitors have apps. They may believe that they need an app to attract the younger generations of customers.
> How is this sustainable?
For a large company like a bank, airline, car manufacturer or grocery store chain, hiring a few developers to build and maintain an app is a trivial expense. They have IT departments with hundreds or thousands of employees. For many businesses (banks, airlines, etc.) the APIs that an app would use to access the customer's account already exist for their web sites.
Celebrities can make a huge amount of money selling products and ads on their app (I seem to remember reading that the Kardashians made many millions of dollars from their app).