In almost all mergers the management of the worse comapny ends up winning, provided there was no loopsided difference in size. The thing is, since those executive were not good at creating product, they are more likely to be good at politics and hence they end up overtaking management of the new combined company, even if their company was the smaller one.
A good series of examples is in the book "Barbarians at the Gate", chronicling the career of F Ross Johnson. His company would get acquired and then he and his folks would outmanoeuvre the acquiring company management.
Boeing was known as a great engineering firm that was not that great at turning their engineering excellence into shareholder returns. The shareholders wanted executives more focused on said returns.
Sounds like the solution is to turn it into a privately owned company then. Of course, that's greatly simplifying things, but it would be a right step in the right direction.
Finance people prefer finance people. MD's bean counter management were seen as being more responsible and "hard nosed" than the Boeing management who were focused on things that "didn't drive the bottom line" like the product, culture, etc.
I recall that in a previous thread, someone had explained that the agreement between Boeing and MD was that MD's management would be retained at similar positions in Boeing, and that many of MD's management gamed this agreement by raising their position before the merger. Leading MD's management to end up higher in Boeing's management.