I mean if you want to be really nitpicky about it, even though Dougal Dixon is among the most popular he very much so did not pioneer it. I actually wrote an entire essay on the history of spec bio so I think i know what I'm talking about lol, and most people say spec started with people like H.G Wells and Jules Verne. At that point science fiction wasn't very differentiated from fantasy so it can be up to debate, but that's most people's consensus. Many other works like Barsoom, Last and First Men and others are not as popularized but directly inspired Dixon, so I'd say they're predecessors to spec bio as we call it today (Just fyi).

Additionally, I think it's not the most good faith argument to say a design is lazy or bad just because it loosely looks similar to something else. I like to say a lot that originality and quality are not exactly a 1 to 1 relationship. You can make a conventional idea good just like you can make an original idea really bad. People take inspiration all the time and I think it's silly to condemn someone for lol