The title of this thread is not totally accurate. It may be a problem for airlines, but they don't see it that way. They see it as a problem of whinging pilots who complain too much when the airlines are working them within the rules as laid down by the world's aviation authorities.
So they see it as they are operating legally and therefore there is not a problem. How many times have you been told when you complain to crewing that: 'it is within the flight crew limitations, it is legal and therefore you can not be tired!'. Clearly being 'legally tired' is somewhat different to the real world.