You'll understand it when you realise that capitalism doesn't just encourage pursuing profit, it encourages pursuing growth.
The "profit" being pursued under capitalism is not the profit of the company itself but instead the profit of the capital-owners with a stake in the company. These people make their profit not from the company being in the black but by the company GROWING. Thus meaning it increases its overall value on the capital markets.
Companies eventually reach a saturation point at which their growth in terms of customers hits a peak, they have acquired all of the customers and aren't likely to acquire more. When this growth avenue closes they must turn to others to continue "growing" the value of the business for the investor class. This is achieved through measures like cost cutting, reducing staff, and installing incredibly bullshit monetisation schemes that either succeed or kill entire businesses in their attempt to continue their growth.
It has nothing to do with "expensive market to maintain". They aren't doing it because they need more money. They do it because they need more growth.
This is also the reason every game you play and liked once upon a time is progressively going more and more to shit.