I think for most people the higher initial cost for a diesel generator would be a determining factor (unless you purchase military surplus),though not answering your question...due to the very high compression ratio needed to ignite the diesel, I don't think there is a "pull rope" start available, and would have the added maintenance of an electric start and battery upkeep....

I would hazard a guess, though, that the inverter generators like the Honda eu2000i, not needing to run at a continuous full power will be the choice for the future... and that individuals will limit the cycle run time of their generators to maintain temperature of refrigerators,freezers and charge batteries, as opposed to a continuous run just to keep the lights on