Imagine a well to do company of 2 founders (in SF/Bay Area) and a team of 3-4 others that raised a seed at 10m cap. They want to grow their team headcount to 15 and are busy hiring, running servers, etc. They can offer a 100k salary (more than enough to live on) to a sort of senior engineer or PM and want to compete with Google on total comp. Let's say they need to make up the other 100k difference in comp & salary with options. Over 4 years, you're looking at a 4% equity chunk to one employee, the 6th person joining the company.
Not that I think numbers in line with this aren't realistic (I do agree with Sam that more generous equity grants are better), but for most companies that make a 15% option chunk for employees it's difficult to rationalize a number like that.
Edit: Also, that puts the equity comp of that 6th employee (or 10th, because in most cases you will have a similar equity bracket for those people) at about 1/8th of the founders, not the 1/200th that Sam mentioned. I wonder how many people have made offers to employees with a similar comp plan.