If my experience is anything to go by those clusters will fade and die over the next 20 years just like the equally critical and irreplaceable unix(tm) vms and

If my experience is anything to go by those clusters will fade and die over the next 20 years just like the equally critical and irreplaceable unix(tm) vms and mainframe system is in the process of doing. But it will be a long process and a lot of money will be made by vmware and partners even as the market wound down and move to whatever it is that going to replace it(im willing to bet it wont be kubenetes as we know it today).