I see 8 teams that need a QB: Indy, Hou, Car, Jets, Raiders, Saints, Atl and TB. I´m not counting Washington since I believe they want to take a look at Sam Howell this year. Tennesee will probably be looking to move on from Tannehill next year, and they can still try and groom Willis.
Out of those 8 teams, Indy, Hou, are locks to take rookie QBs, and the third and fourth best could potentially be taken in the top 10 draft positions. In that case, Atl, Raiders and Car could potentially be looking at a rookie 1st round QB as well. You have to eliminate the Raiders from the "Carr sweepstakes" no matter what.
By this logic, the only teams that could really be interested in Carr (because they are not in range to draft a top tier rookie QB) are the Saints, Jets and Bucs.
So the market kind of checks out. Carolina could just be doing this to drive the price up for the Saints, I don´t see why they would be interested in Carr with a top 10 draft choice in their pocket and draft capital to move up.
And there is still the probability that Rodgers and Jackson get traded.
If the Saints are smart, they know that Carr doesn´t really have much of a market and they are offering him a team friendly deal, hence the hold up by Carr.