They're spending it now, in an attempt to make sure that never happens...
bingo!
How wonderful it is to agree!
DL employees don't see the need for unions when they are paid as well as or better than their peers at other airlines - and DL is creating jobs by bringing work back inhouse and adding pay while other carriers either continue to outsource work and/or hold employees at their previous BK rates.
DL's practice of paying its employees "just a little more" than its peers goes back well before deregulation. DL's current management has been smart enough to look at what made DL tick in the past and work to reinstate many of those same things.
I don't for a minute doubt your observations as well as the accounts you have cited about what some people are experiencing and forgive me if I sound flippant at your efforts to advance your cause.
At the end of the day, DL is looking at the total odds of remaining non-union and isn't afraid to throw money at its employees to keep the values that have enabled the airline to succeed where others have not. The fact that DL is running a profitable airline is precisely what drives their ability to keep throwing money at employees to keep them non-union.
The vast majority of employees are able to look past the issues you cite precisely because of the better total compensation than their peers - compensation which continues to grow even after adding in higher health care costs which is an issue for all American workers. Add in the jobs which DL is shifting from DCI back to mainline and it is very hard to argue that unions would provide a better compensation package for DL employees.
And it bears noting once again that labor relations are horrid in the airline industry; most airline employees have working relationships w/ their companies that are just as bad if not worse, but obviously perceptions of "justice" and "treatment" are subjective and differ from person to person.