If they are used to produce many orders of magnitude more plots than could fit on them. His point is you don't need SSDs to plot, and can reasonably make them directly on the spinning HDD on which you'll store them. I know, because I'm doing this. I make one plot in about 10 hours on the 7200rpm commodity drive in my home media server. It may take me longer to fill up my space than it would with an SSD, but compared to the amount of time in the future I'll be able to farm the plots it doesn't really matter. Cranking out plots as fast as possible probably only helped for the first week or two.
People are burning out SSDs since they're buying into the arms race and trying to get/stay ahead of the netspace growth, hoping for some "easy" XCH, but that's a choice they're making, using poor (or more likely no) ROI calculations and outdated information.
No one is claiming that Chia is burning hard drives. He is intentionally being misleading. Chia absolutely destroys consumer SSDs.