Changing to a different paint color would be quite risky for any manufacturer. Marketing is tied to a certain color. People associate certain colors to certain equipment.
Just look at John Deere. They have always been green w/ yellow accents, except for their construction line. Can anyone ever see John Deere switching to blue or red? Proabably not.
Should Grass Hopper change it's colors? Grass Hopper knows that when you see that color mower out in public, you are not confusing it with something else.
If one of us was a president of a major maufacturer, I am sure that we would not change trade mark colors unless we were assured that It would create more sales and not hurt our reputation with current owners.
One small color change would be tough to pull off.