Why aren't they paid when they're in the airport between flight? At the layover hotel, away from home, while on their trip?

How was their hourly rate established? Would it be the same hourly rate if they were paid for all those other times when they are not on an airport or the airplane door is not closed?

The traditional model pays pilots and flight attendants a higher hourly rate but only from block-out to block-in. Would a lower hourly rate with expanded start/stop times be a better system if the end result is about the same amount of pay?

There has been a push lately to pay F/As during boarding at 50% of their normal rate.