BlackBerry the latest tech empire in rapid decline

Forbes magazine reports about RIM, the company producing the once-incredibly popular BlackBerry, is laying off top execs following a 75% fall in share value just in the last year. Details are provided of sales of other similar products (e.g. the Palm, or Nokian products) have declined rapidly. The question they raise, too, is, if other companies which were once favourites can fall out of favour so quickly, how can Apple avoid that fate?