I think you got it right. Many pacers are bred with the sales ring in mind. Trotters are bred with the race track in mind. With the recent success of the trotting sales that will start to change.
Look at the APG sales , if they're not by one of the top 6 or 7 superstar stallions they wont even get in the main sale. Just another way these sales are changing things for the worse . I think they concentrate too much on who the sire is and not who the dam is.