The other large pyramids were built within a couple of centuries of the great one. I have also read the there was a slight indentation on all 4 sides so that a surface had a faint path for water on each smooth side. Eventually, people started stealing the smooth covering for building other things.
The limestone casing blocks were plundered by the muzzies to build medieval Cairo. Some of the original casing blocks remain on the upper fourth or so of Khafre, the number two pyramid at Giza. One of the moron caliphs decided to destroy the Giza pyramids, and had his workmen start with Menkaure (the smallest of the large ones); after six months, they had accomplished the damage still visible today, but it obviously going to take a really long time to tear down that one, and the other two are about an order of magnitude greater, each (from the wiki-wacky — 91,227,778 cf, 78,084,118 cf, 8,305,409 cf).