I dont know if this is necessarily true (not that you said it is)
I looked at the salaries of all teams top 2 C and you will find that most of the teams expected to express interest, or who make sense as a landing spot, have very little $ spent at C
TOR - 22.63m (Matthews + Tavares)
EDM - 21m (McDavid + Draisaitl) or 18.5 (McDavid + RNH)
PIT - 18.25m (Malkin + Crosby)
LAK - 15.27m (Kopitar + Carter)
WAS - 14.5m (Kuznetsov + Backstrom)
BOS - 14.125m (Krejci + Bergeron)
ANA - 14.075m (Getzlaf + Henrique)
* NAS - 14.0m (Johansen + Turris)
PHI - 12.58m (Giroux + Couturier)
STL - 12.5m (O’Reilly + Bozak)
*DAL - 12.05m (Seguin + Faksa)
CGY - 11.725m (Monahan + Backlund)
SJS - 11.625m (Couture + Hertl (Pavelski + Thornton = UFA))
WIN - 11.41m (Scheifele + Little)
* ARZ - 11.4m (Stepan + Galchenyuk)
VGK - 10.35m (Stastny + Eakin (Karlsson = RFA))
DET - 11.35m (Larkin + Nielsen)
CHI - 11.35m (Toews + Strome)
COL - 11.05m (Mackinnon + Soderberg)
* BUF - 10.65m (Eichel + Rodriquez)
FLA - 10.65m (Barkov + Trocheck)
TB - 9.28m (Stamkos + Cirelli)
* MIN - 9.0m (Koivu + Staal)
* VAN - 8.5m (Horvat + Beagle)
CAR - 6.675m (Staal + Walmark (Aho = RFA))
* NJD - 6.675m (Zajac + Hischier)
*CLB - 6.4m (Foligno + Dubois (Duchene = UFA))
*MTL - 6.23m (Domi + Danault)
* NYR - 6.23m (Zibanejad + Howden)
*OTT - 6.03m (Pageau + Tierney (White = RFA))
* NYI - 4.2m (Cizikas + Barzal (Filppula + Nelson = UFA))
The exceptions are:
Nashville, who would only make sense if Turris disappears
Dallas, who have a need for a 2nd line anchor + a healthy amount of capspace due to the impending departure of Spezza
Arizona, who have two mediocre centermen, ample cap space, and are a young, fast team who would be looking for a true #1
&, to a much lesser extent, Buffalo, who has almost all of their money at C tied up in Eichel and no real tenable option at 2c
I do think if you look at it, most of the teams who are heavy players on Duchene will either have the ability to offer him the #1 C position, or they will make him the star of his own line which is what he was in Ottawa and is, to some extent, what he is in Columbus although he at least has Atkinson now. Persoanlly, I think Duchene is best suited to being on a line where he is asked to create most of the chances because thats what he excels at. All he needs is guys who can do some of the dirty work, engage on the cycle with him, and get to the net and finish.
I think it takes at least 8.5m but I do think the Habs are one of the teams who a) will make a big push and b) who he will strongly consider