It's a non-issue, and in fact the reverse is more true.

Nowadays most of the tickets sold by most airlines self-destruct if you don't show up for your flight. That means the airline gets paid for the seat even if the passenger no-shows. Some high (sometimes very high) tickets don't suffer this consequence, and no-showing is on of the benefits you are paying for when you purchase this type of ticket.

But even then the flight is often oversold. If it's not oversold, then it's likely there simply wasn't the business to fill the flight, and the seat(s) would have gone empty even if everyone did show up. On the other had if the flight is oversold, not only does the airline get paid for the no-show seat (in most cases) they also get to resell the seat a second time, and double dip, getting paid twice for the same seat.

On the other hand, the protection for the passenger is often trite in comparison. While the airlines are happy to stick it to passengers who no-show, they are equally happy to sell the same seat twice or more, then leave people behind if everyone shows up. There is usually (but not always) compensation for this. But even if you get $200 or $300 or whatever, does that adequately compensate someone who needs to travel urgently, whether it be for a business meeting, a funeral, or to catch a cruise ship?

The problem the airlines are suffering now is that for almost forever, airlines have operated on their own rules, without a hint of morals or ethics. Advertising one-way fares when return purchase is required, double selling seats, or claiming "weather" as the cause of the delay often when it is not are only a small sample of some of the tawdry practices airlines have employed for years. It's just that consumer activism (and to a lesser degree the competitive market) are finally catching up to the airlines.