not really ever, nor should it. it would cost billions upon billions of dollars for every industry to switch to a metric format for, i am being literal and accurate, zero benefit.

us customary units are fine, they are defined by the SI physical standards and so are just as consistent, precise, and functional. this sort of desire also misunderstands what unit systems are actually like in practice. cgs or mks or xyz are just a surface display, every industry, metric or us customary, has dozens of units specific to the processes relevant to that industry, that are insane and annoying and unintuitive. switching to a metric format does nothing to alleviate what is actually annoying about units (which isnt actually the units but the dimensions). there are some cases where it might, but ultimtely unit conversions are so incredibly trivial that it doesnt ever matter that much. but re designing every calibrated tooling or device and drawing to use a new format? unfathomable time, effort, and introduced opportunities for error, insane costs, wastes of time. eventually in some indeterminate future enough industries will have had to redo most of their standards enouch times that they may be mostly metric anyway, but that's probably quite a ways away. many decades, a century, hard to say. some industries still use units that are hundreds of years old.

tl;dr it's not boomers it's industrial momentum and isnt even useful to anyone to change.