I wouldn't be surprised if there aren't rules in place on the distributors preventing that. Having two distributors jostling for the same space seems like a recipe for stepping on toes.
There is another thing in the economy of newspapers and newspaper distribution: ads. Historically, newspapers have received half of their revenue (and sometimes more) out of advertising. Comics might be a little different, but ads were still present. But that market is entirely different today. American comics doesn't seem to have had outside ads since the 80s or so, and I just checked some new Swedish ones we had lying about, and they didn't have it either (ads for new albums from the publisher, but that's not a revenue generator).
Distribution was only one half of the puzzle here. Revenue is another.