Spencer
As for rockit, there was a ton of techno and italo disco made before that, among other things. It hardly "started everything".
Not sure how you include "italo disco" as dance music in the sense of EDM, but anyway. And if you can point me to anything that remotely sounds like "modern Techno" pre (Rockit 1983), go ahead. Mantronix followed not long after with the "Rockit" sound.
As far as i'm concerned "Hardhouse" was the original Techno as we know it today... early 90's, then all the spin-offs took their cue from that, Trance, Jungle, Happy Hardcore, Dubstep etc, and now the slew of 'me too' 'sub-genres' that we have these days which i deem as more 'experimental', i don't see them as legit "genres". Hardhouse was the original "four to the floor" Genre, and the fact that it still very much thrives today is a big testament to being the grand-daddy foundation of EDM.
I don't follow any particular producers when it comes to Hardhouse, too many out there, i simply follow the scent and feed off the palette. Looking for whichever track nails it. The only time i've heard Hardhouse reach 150bpm was when the DJ was high or drunk and abusing his BPM slider on the Record Player. Happy Hardcore might regularly reach 150bpm though. I find most Hardhouse sits around a sensible 140-144bpm mostly.