You might assume that pilots and airline staff don’t care if your flight is grounded or not, but that’s not true. They only get paid for delays if the doors of the aircraft are closed.
If the delay occurs before people get on the plane, then the airline staff and pilots are also just wasting their time. That’s why engineers will often try their hardest to repair planes as quickly as possible, because they know it can be costing their colleagues precious earnings.
Staying fit is certainly a commitment. Besides doing the physical training, there are some other factors to consider, like nutrition