The growth and decline of Intel's stock offer lessons for today's investors.Intel (INTC -0.04%) has struggled in recent years as Nvidia and longtime rival Advanced Micro Devices began to surpass it technically. So far, efforts to catch up have fallen short, taking its stock to multiyear lows.Its recent performance may make investors forget that it developed the first commercially produced microprocessor and was the world's largest semiconductor company for most of its history. Since its initial public offer ...