My guess is that the 3 man ULR is here to stay. They do not have the man power to properly staff the schedule now and even if pilots came "en masse", it would take a minimum of 3 years before the line guys would see the benefits.
So its not even a question of pressing 2 anymore for your health, its really a question of pressing the "submit" button of your resignation email, your health is a long term investment as opposed to a couple days off here and there. Everyone also knows that they will start probing in to the question of " why you are not rested" with the 10 days off per month you get"? "Do you snore?" will be asked and then it gets interesting from there...ask some guys who have gone through it.
In any case, the trend has been downward, my guess for the next "knee in the package" will be income tax among other gems, a reduction in leave which has been tried before.
The trend however has become serious as it appears "safety third" has become the truth.
Stay safe.