You're probably right about that. That happens at any office work place settings too. Difference here is, you are in a customer-facing job, where your attentiveness and face you put on impacts customer satisfaction. If you can't keep customers happy as well as a 25-year old, then you don't belong in the cabin.
Look, I don't blame the front-line workers for any of this. This is almost all management's fault. Look at Southwest. Their attendants are better trained, more motivated, and are happier.
Better work environment and management are important, but they're paid 25% more than other airlines. SW will attract better talent and retain them. I'm sure other airlines wouldn't mind having SW style employees. But their management is not willing to pay for it.