Because they all have the prudence and insight to be long on silver.
"Warren E. Buffett purchased 129.7 million ounces of silver in 1998. He must believe in its worth. George Soros and his Quantum Fund own 32 percent of Apex Silver Mines (SIL). Bill Gates owns at least 10 percent of Pan American Silver (PAAS)."
The above is a seminal exerpt from a longer post that I placed earlier on silver for those who don't like reading long posts.
Silver, like gold, is soon to have its day in the sun.