I would guess that most people are simply leaving it that they have less withheld and therfore a larger paycheck and a lower refund and are unsure whether or not they are paying more or less overall bottom line.
No just the opposite. They feel they got screwed. Seeing a 5-10 dollars different each week goes unnoticed. Getting 400-500 less back at the end of the year and they are up in arms.
How can the people you know not seeing less when they do their taxes? All things being equal because of the games they played with withholding they should get less or have to pay more at the end of the year.
You really do need to get out more and see what the average American sees.