The stock price still matters, though. Executives and employees holding stock or options benefit when the stock rises. If the company wants to issue more stock, it will want to do so when the price is higher rather than lower, to generate more capital for fewer shares. If the company is buying another company with its stock, the higher the price, the more bang it gets for each share. Meanwhile, a company's falling stock price may make it more attractive to companies thinking of buying it.
Stock is a form of capital, and companies often hold a chunk of their own stock.