Why buy cheap speakers??

I look at some of the systems on this site they have only the best electronics and sub standard speakers? I was taught to spend 1/3 to 1/2 on speakers and the rest on the entire system. I see $500.00 speakers with $3000.00 transports or turntables. That is such a waist of money. Speakers are the most important part of a system or so I was taught. Am I wrong? Help me out here.Why put $300.00 cables on $300.00speakers makes no sence what so ever.