Kamara put up a
high end statistical season with an 18.5% DVoA (4th in the league among backs) and a 58% Success Rate (2nd in the league). DVoA is an explosive play metric, whereas Success Rate is your ability as a back to pick up the required yards at a minimum. Guys who can provide both are the prototypes for today's offensive backfield.
Then last year and following the departure of Ingram (who had top numbers in both metrics in 2018 and again in 2019) we saw Kamara take a big dip. Probably had to do with teams knowing who he was and that he'd get the ball more in certain situations, but his DVoA slipped to 15th and his SR to 12th. So IMO it's wise for the Saints to be careful how much they're paying him. Is he a guy who will struggle when he's the guy, i.e. the type of back who needs a stable around him? Or was last season due to some other factors.
I don't know the Saints' OL all that well (I don't really look at their film outside of some matchups with us) so maybe there were some other things involved. But I think Sean Payton takes the right approach on a lot of things and that includes this situation.