Would Janeway have diffused the Dominion War, made it a hundred times worse or had zero effect on DS9 entirely? Besides, if the Val Jean was still taken (And Voyager wasn't.) that would have meant that Janeway not only failed in her mission but that she lost Tuvok. You can lose all the 20 year old human Ensigns you want and nothing, but if you "misplace" to death a hundred year old Vulcan Lt Commander... If you don't lose your ship for gross negligence, then surely the Admiralty is going to have zip confidence in your style and you're allotted with bullshit unimportant nowhere assignments for the rest of your career like guarding latrines.