This is true of aviation worldwide, and on a wider scale of business in general. They are not fixed entities, they rise and fall.
What you find is that over time many of the routes, the passenger numbers, even the crews, carry on from one to the next. It is just the corporate structures and the colour of the paint on the aircraft that come and go. Palma is still a huge destination from many UK airports, it's just that the airline names differ now from those of the 1990s, which in turn were different from those of the 1960s.