This is my very personal opinion: despite this very difficult period, which will surely weaken many companies (as aviation is a very fragile toy), even though some other airlines might go to administration, with loads of pilots on the ground, there will always be for sure the need to fly.
Other companies may expand, or maybe others more will born, the sky won't be empty when this disaster will end.
Considering that is not easy to contain a virus when already spreaded all over the world, the real antidote which will take away the fear of being infected, and so others fears such as to travel, from people mind will be to find a vaccine.
Only then the world will go back to the normal.