Top Lights is a spin off (former employee) of SPJ. The reality is SPJ was the originator. Nate and Unique got their fixtures from SPJ when they first started, then after building traction, Unique went on their own. Rockscapes also came out of SPJ, and after the owner sold Rockscapes, he has then started and incubated several other smaller manu's. Cast came out of Unique. Cast founder was one of Uniques largest distributors who then went on his own. If you want to play fair, you could say SPJ was the first and major originator of what you call the ubiquitous fixtures--and Unique and Cast came out of them. The reason most don't realize this is because they companies that use distribution channels have 1000's of sales people and dealers telling them that the dealer supplied products are the real products and everything else is garbage.
I will acknowledge that 95% off the ubiquitous fixtures are not comparable to Cast or Unique in quality, components, finishing, reliability, innovation, support. Additionally Cast and Unique are "real" companies that support the industry, quality and innovation which in my eyes makes them very important and valuable.
Obviously, I am touting my own horn, but that is because I believe there is a great comparative advantage of using a factory direct manu IF you can find one that has a quality product and is a stand-up company (which includes having inventory, support, innovation, quality). It will bring more power to the contractor and eliminate inefficiencies that hurt that contractor.
Just as some take an LED light made in china with the same casting and heat sink and then install their own components. Its all standard business. For the record, I have nothing to do with any of the companies I mentioned, I'm not defending them, just stating it how it is.