Reinhold Messner was the first to propose a simple but effective solution: ban the use of bottled oxygen and sherpa support above 20,000ft.
90% of the “climbers” would never show up under such conditions and most of those who did would have to quit well short of the summit.
Messner climbed the north face of Everest solo, in winter, without oxygen, sherpas, or any support beyond his girlfriend waiting anxiously in a tent below and the pack on his back, so his word carries some weight in these matters.
Actually, I have read it costs $65K to get your shot at going to the top with one of the best guides. Keep in mind the reason it is so crowded is because May is the best month for weather. The rest of the year is almost immpossible to get above 20,000 feet. Also, 90% as the climbers go up the south face in Nepal. It is much more diificult to get the permit to go up the north face in Tibet since China took over the country. Also the north face is a much more difficult route.
Keep in mind that the people who make their living providing the guide service make most of their income for the year in a 1-2 month period. As somebody already suggested, it would eliminate 90% of the climbers if you were not allowed to use oxygen. However, it is up to Nepal and China to make that decision. The mountain is in their country. It brings a huge amount of revenue into that part of the world. After all it is all about the money.