This phenomenon is not limited to tech industry, tho it might be most prominent/visible there. I work in media production and I see exactly the same thing. It’s the age old “work from the bottom of the ladder” principle which may have made sense back when jobs were basically for life but now, in the age of “temps” and such it’s become nothing but a big lie - and you can see it pretty much everywhere from hi-tech and IT to consumer retail. It’s extreme capitalist exploitation with all holds removed in an increasingly transparent shiny plastic wrapper.