Why are my tires cupping? Shocks good wheel bearings tight, tires rotated every 5000, Front end not out of line.?

Tire cupping is generally cause by a failing or failed suspension component or simply a sub-pair quality tire.

If the tire itself is of poor quality it can develop cupping even if your vehicle's suspension has its integrity.

Did you have your tires balanced again when they were rotated?

How did you test your struts? Bounce test is NOT a valid test for struts

http://ricksfreeautorepairadvice.com/how-to-test-s...

Tires cupping is usually bad struts or shocks.

If both front tires are worn on the inside edges there is too much toe out. If the front tires are worn on the outer edges it's from too much toe in.

Have the control arm bushings and ball joints inspected.

Usually worn shocks. If you say the shocks are good then wheel maybe out of balance. If pairs of tires then the double check on the shocks.

If everything is good as you say it may be poor quality tires or just the way the suspension of your unknown vehicle moves. Older Ford trucks use to be notorious for wearing out front tires because of the way their twin beam front axle changed geometry as it went down the road.

Wrong air pressure.