I think it's because amps and wires are so much easier to change out compared to all the big bulky expensive speakers.
If they can convince themselves that amps will improve the sound, it would be so much easier to do than change out speakers.
I like my DefTech system a lot. But man, the BP7000 were like 160lbs each x 2, BP7001 were like 130lbs each x 2, CLR3000 was like 80lbs x 1, Trinity was like 200lbs x 1. That's a lot of bulk and weight to change out - pack up, sell, ship, etc.
It was so much easier selling my Emotiva MPS-2 or Acurus amps.