"I don't think there are any public figures on how many 7-Star players Harrahs has but my guess would be only a few hundred."

I think you might be underestimating a just a tad bit...

At my property we have over 150 7 Stars assigned to our property (dominant property - where they play the most) and this is a smaller property. Also to renew as a 7 Star (after the 100,000 the first year) is 80,000 points.

1 Seven Star = 14 Diamond players in theo win.

1 Diamond = 54 Gold players in theo win

Why Does Harrah's have Diamond lines?
So having one Diamond player in line is like having a line of 54 Gold Players - That's why Harrah's has Diamond Lines.