Yes, I agree with you, the absolute worst case scenario would be to have only one team in the running for a DeBrincat trade. IMO structuring the process in this way where teams can only to talk to the DeBrincat camp once they have tabled an acceptable offer increases the chances that there will be multiple teams involved. What we wouldn't want is DeBrincat deterring teams from getting involved at all either with unrealistic contract demands for certain destinations or an outright refusal to sign with a potential suitor, we want to be able to leverage those teams' offers in negotiations with other teams before they drop out of the process.
I also was not trying to equate DeBrincat to an NFL QB, I understand that the value of those two assets are in completely different stratospheres. My intention was rather to show the analogies in the two situations where there is/was a GM with 1) an asset that they have to move and that is expected to garner interest from multiple teams and 2) is/was trying to maximize the value of that asset in a trade where they were hindered by a restriction (Watson had a NTC; while DeBrincat does not have a NTC, his willingness to only sign an extension with a limited number of teams kinda forces Dorion to treat the situation as if he did have a NTC). I was also trying to point out that we should not be overly critical of Dorion deciding to structure the trade process as it was reported because the same method has been used before (albeit in a different pro league with a more valuable asset) and it was successful.
My example was also just something I made up to illustrate how I imagined the process to play out, I wasn't trying to imply anything about DeBrincat's market or the number of interested teams. I actually think that for a player of DeBricnat's calibre, his market will be rather thin for the exact reasons you listed (cap situations, teams having more pressing needs, cheaper alternatives being available, etc). I think that in the best case scenario, there are 7-8 teams that kick tires, do their due diligence, feel out what Dorion is looking for. Then out of those 7-8 teams, 3-4 teams get more serious and deeper in negotiations and then if the offers are good enough, Dorion gets to narrow it down to his preferred 2 or 3 offers.