Tha's a risky move for Quinn IMO. But glad to see him stay.
Why is it risky. There will be HC openings next year as well. Maybe he did not like the situations with any of the teams.
Improve the defense and go further in the playoffs, his asking price could go up.
Maybe the team did not want to pay that much more for him to stay in Dallas, and Texas (no state taxes) to eat at part of the pay.
Maybe teams did not want to give the freedom as a HC would want, or to hire his own staff. Many reasons involved from both sides.