The car maker claimed that they focus on the long term growth of the company which should maximize the wealth of their stock owners. Furthermore their business is strongly influenced by seasonal factors. Thus 3-month-reports aren´t a meaningful base of information for the stake holders, they said.
Porsche was right. Quarterly numbers reflect a lot of random factors. The reported profits could swing erratically because of sudden changes of tax rates, accounting methods, swings in foreign exchange and interest rates, fluctuations in consumer spending and many other causes. For instance, if customers are waiting on a product update, maybe a new car model, the sales of the current product can temporarily sink and blur the quarterly results.
If management feels obliged to deliver high profits in every quarter to please the myopic crowd of analysts and fund managers, it could be forced to avoid necessary expenses which would temporarily reduce profits but boost company income in the future. The company could invest less in new products and markets because this causes high costs at present. Hence focusing on quarterly numbers discourages research & development and slows down the growth of the whole economy.
Because of their randomness, quarterly numbers produce a lot of noise and smoke which can spoil the view on the long term trend. Companies like Amazon.com ignore the myopic view of the stock market and invest for the long term even though this could cause erratic stock price fluctuations. But they do pretty well over the long run as the stock performance in the recent years proves.
Disclaimer: I am invested in Amazon.com.