I get what you're trying to say, but the context of the Christmas truces is more complicated than just mutual benefit:

There was a huge disconnect between the leadership of the respective armies and the rank-and-file soldiers dying in the trenches. So it wasn't just "its Christmas, we shouldn't be killing each other", it was also "we have no idea why we are fighting in the first place, and our leaders think it more important that we die than that we win." It was deliberate insubordination to what the soldiers understood was pointless wasting of their lives.

I think the correct analogy is if the workers of Airbus and Boeing both struck because the two companies had both adopted new business practices in the name of business competition, that simply killed workers and passengers without providing either with any kind of competitive advantage.