I disagree. How do you increase your income if you don’t invest in your product? Everything is fine in a business until it’s not. I’ve spent years in an industry where new product is launched multiple times a year. The cost of new product is very large. If you wanted to run things on profit alone, you’d cease/reduce new product, the saving would be enormous. For 2 or 3 years you’d have large profits. After 2 - 3 years sales would likely decline to the point the business was no longer profitable. It’s simply a balance between refreshing/renewing your product, and maximising your income.

If it were as simple as you say why would any airline invest in new product rather than just work with what they have?