For so many obvious reasons.
They already traded far too much to land Goff, which, IMO, was a huge mistake and said so at the time. Trading now for the Saints' coach would just double down on depleting the roster, and the talent-base needs major upgrading, not depletion. They weren't just one player away
before the Goff trade, and they're even further behind the eight ball now. Giving up more draft picks would set them back years.
In fact, if any team had wanted to trade for Fisher before the Rams fired him,
that would have been fantastic.
;>
The Rams, in short, need to be on the receiving end of another team's desperate moves. They can't afford desperation themselves.
There are dozens of coaches, or potential coaches, who could do at least as well as Payton, and cost the Rams nothing. If they're smart, they'll avoid any coach who requires compensation.