In fairness to the Pistons, they did buy low and sell high.
They bought low on "one of the premier perimeter defenders in the NBA". Boston gave them a second and Bradley for Morris. Bradley's reputation is considerably bigger than his on court play, yet he still is coveted by teams looking for a 3-D player. He has a career 107 defensive rating, a career negative box score plus minus, and he is undersized and not switchable. Did you know that he has a career 99 offensive rating? Even on good offensive teams, his offensive rating was below average, probably largely due to his inability to create for others or get to the free throw line. Did you know he's a 37% 3 point shooter? That's respectable, but not exactly JJ Reddick. Its not like they were going to resign him after this season anyway.
They bought low on Harris from the Magic. They inflated his value all season. Did you know that he didn't even start half the games last year because Morris started over him? Did you know he averages 3 FTA per 36 for his career? Did you know that, even though he is shooting 41% from 3 this year, he is a career 35% shooter. He has averaged 20 ppg this year, but its not bringing his team wins. 20 ppg scorers on losing teams are not as impressive as 16 ppg scorers in winning teams.
Its not like their draft picks have been any good, either.
The Pistons bought low and sold high. They have a more exciting team. They have higher upside for at least the next 3 years. And they didn't have to trade Johnson, Bullock, or Kennard, which gives them the flexibility to try to land another solid rotation player, or continue to develop from within.
Don't get me wrong, the Pistons aren't competing for a championship -- they are now a perennial treadmill team. But their immediate future is much brighter than it would have been with Harris, Boban, and Bradley.