I think we're tackling this from the wrong end as it were.
When I did my commercial pilot training back in 1969 our course was taken to the nearby Royal Navy base where we did the hypoxia training - put in a chamber, taken to circa 40,000 feet pressure and given simple tasks to do having switched the oxygen off etc. This was done one at a time and it was an interesting experience to watch my colleagues' performance when subject to hypoxia.
It's an experience I have never forgotten and we were left in doubt about the dangers of hypoxia in flight.
In my opinion all those who fly pressurised aircraft should do hypoxia training and this would go a long way to avoid these sad incidents which happen from time to time.
Also it is essential to check oxygen systems for quantity, supply, correct fitting of mask prior to flight. At the slightest hint of a pressurisation problem oxygen masks should be donned.
Regarding descent with ATC a pressurisation failure is a MAYDAY as far as I am concerned. Also the whole idea of using the priority calls (MAYDAY or PAN, although the latter is not recognised in some states) is to draw immediate attention to one's plight. A vague request for descent on a busy ATC freq is never going to get the same attention as calling MAYDAY and/or wearing the 7700 badge if necessary.