Look at death metal now, it is almost certainly going to have "clean " lyrics in there too. I don't recall anyone doing it before Fear Factory did. If you know differently, we should talk. I don't pretend to be the authority on this subject. I am just speaking from my own life. The world of metal owes a lot to Fear Factory IMO.

I feel bad for FF, because i don't think they actually ever made any money
This doesn't mean i am correct. I honestly don't know if i am.
It just means i am subject to the opportunities to view things / life through my own eyes. However, if i am correct. The people who have made loads of money by taming down death metal to appeal to a wider audience owe a bunch of money to Fear Factory.
I first encountered Fear Factory completely by accident at a festival i was attending at Brandywine, Maryland purely because Obituary was headlining it. I had heard a song or two by them prior to going to this show but while i was in the (poorly attended) field watching them warm up for Obituary, I noticed one thing... This was the first time i had ever heard vocals in a song in this sort of metal that I could actually understand the words. The singer actually had kind of a nice voice and it was melodic.

I know that is common now, but back in 1992 that was extremely rare, if not entirely never-done-ish.
.... i was completely blown away because at that point of my life I had never heard anything like this before and i wanted more. It was completely unknown to me that the rest of the industry would wait 10 years and then do exactly that. No one had ever heard clean and growly voices from the same person in the same band, ever.
This is the only song that MAYBE anyone who is not a die-hard metal fan might have heard.

there is not a video since the band members could probably barely afford the gas for their reapey-looking van at the time
Let's get one thing straight: Fear Factory is NOT by any means, a legendary band. They have a relatively piss-poor record as far as sales are concerned. I just think that for whatever reason, they happened to stumble on something many years before someone else figured out how to monetize it and they deserve credit for it.
I heard it because i happened to be really really into the scene at the time. I'm not special, i'm just lucky i guess.
I'm not trying to say that Fear Factory is bad. Please don't think that. I am actually trying to say they may have accidentally (or intentionally) invented modern-day death metal.