Agreed, you'd wonder why then considering its pedigree that it isn't more widespread in diving...maybe because it isn't a shiny piece of equipment with an easily recognisable result. When the number of reported incidents is low, and fatalities much lower, risk perception is low.
In military aviation it took more than 15 years for CRM to become part of the fabric of operations and there are still issues like landing with the gear up... Whilst healthcare and medicine have embodied HF training across the spectrum, HF isn't just about CRM training, it is taking a system's view of the problems. Checklists are not the whole solution, they are a catalyst and enabler for improved communication, situational awareness and teamwork.
If consistent issues are happening at the sharp end (diver, surgical theatre, aircrew), then it is not likely to be an individual issue, but rather a system problem. CRM/Non-technical skills can help address some of the residual issues but the true solution must come from the organisational level.
Regards