Well, it's still a fun Fermi calculation problem, anyway.

Let's see, the Pyramids have been the targets of tourism since at least the original catalogue of wonders of the ancient world, Antipater of Sidon ~140 BC which includes "the great man-made mountains of the lofty pyramids". So that's ~2150 years of tourism (2012+140). Quickly checking, Wikipedia says 12.8 million people visited Egypt for tourism in 2008, but surely not all of them visited the pyramids? Let's halve it to 6 million.

Let's pretend Egyptian tourism followed a linear growth between 140 BC with one visitor (Antipater) and 6 million in 2012 (yes, world population & wealth has grown and so you'd expect tourism to grow a lot, but Egypt has been pretty chaotic recently), over 2150 years. We can just average that to 3 million a year, which gives us a silly total number of tourists of 2150 * 3 million or 6.45 billion visitors.

There are 138 pyramids, WP says, with the Great Pyramid estimated at 100,000 workers. Let's halve it (again with the assumptions!) at 50k workers a pyramid, 50,000 * 138 = 6.9m workers total.

This gives us the visitor:worker ratio of 6.45b:6.9m, or 21,500:23, or 934.8:1.

And of course the pyramids are still there, so whatever the real ratio, it's getting better (modulo issues of maintenance and restoration).