Went through two acquisitions.
There was always a salary hike, some sum from the equity (life changing for early employees) but what majorly mattered was our ability to establish ourselves inside the company, create relationships and value. The leadership is not always going to show you the way to do that.
Most of my colleagues from the first acquisition and still in the same company, only a couple switched to startups. While the second acquisition, most people except the founders and founder -1s have been laid off.
But generally work slows down, politics increase, some people might give up and switch for smaller teams while some will enjoy the perks if they get any.