This you are talking about is the reason why some airlines (non European for the most part) have kept current and on payroll all their pilots. They want to ensure the livelihood of their colleagues and at the same time betting on being ready 100% when and if things seriously pick up again.
There is no way to hire, train and keep people once and if things seem to pick up.
I for one really hope that companies who are doing this will benefit big time, and take the biggest possible market slice when and if we get to the other side.
Having said all this, if this madness starts again next autumn then..