What fans though? The reason F-Zero hasn't had a game in 20 years is because the original on the SNES was by far the best selling game in the franchise and every sequel, sold worse and worse. The original SNES game sold close to 3 million copies, while the N64 sequel barely passed 1 million, despite the N64 game being a huge upgrade in players and content. Then you have GX which has even more content, and was obviously very expensive to make, sell even less. It was one of the few Nintendo games on the Gamecube that couldn't even cross the one million mark. Then you get the two GBA games based off the anime which were two of the worst selling Nintendo games of all time.
Whoa, whoa, whoa, whoa, whoa, whhhoooaaaaa! First, the SNES game had a partial advantage of being a launch title with the SNES. I don't know how many copies Nintendo made of that game but, back around 2003 or 2004, I was able to buy a still shrinkwrapped Player's Choice copy of the game for 0.10 off eBay because the demand wasn't there for the title unlike other SNES stuff. How did so many copies of that game still end up being for sale new at that time? I don't know but it may have been that people could pick them up cheap later on in the system's life adding to those sales numbers and make it the "best-selling" title in the series.
As for F-Zero GX, word on the street was that it crossed 1.5 million and this knowledge came about 5 years ago from Nagoshi himself. Here's
Nintendo Life's article in which he states it at that amount and being proud of the sales for it. F-Zero GX also made the list of Player's Choice games on the GameCube and had some copies made with the yellow branding which meant it was at least a million seller. Considering GameCube console sales were much lower compared to SNES and most other Nintendo consoles, the fact that GX did about half the SNES sales is actually a positive thing showing why the demand is there for a follow-up entry.
As for the GBA games, first there was Maximum Velocity (which was not based off any F-Zero anime but you probably weren't referring to that one). However, it should be commented on because it is its own weird thing. It goes back to the 2D racing after having 3D from X. Much like how Mario Kart Super Circuit just doesn't cut it after MK64, MV just isn't that great by going back to the SNES look and feel. Even weirder, the game takes place 25 years after the days the SNES F-Zero so it doesn't have Captain Falcon or Samurai Gorah as playable options but rather a whole new cast of characters. Pretty much all the race tracks are different worlds/places from the commonly used stuff. None of these characters and most of these track names are never used again in any F-Zero game which makes it a bit weird to call it that. Imagine Mario Kart that supposedly takes place in the future so you've got brand new characters you've never seen before racing in completely different worlds. Maybe the gameplay is similar but it just seems wrong.
F-Zero: GP Legend is based off the F-Zero anime and is the game that I shoulder most blame on for "killing" the series or at least keeping the series dormant for so long. I guess Nintendo hoped to capitalize on the anime that was done and the positive reception of GX and AX which led to them releasing another F-Zero game on the GBA but it was a poorly timed decision. First, if the anime played in the West, I never saw it on TV or knew about it until way after the GBA games were no longer on the shelves. Second, did the GBA really need a second 2D F-Zero racing game? No system had ever had two F-Zero games before. Did Nintendo really think this was going to explode? You had Maximum Velocity in 2001. F-Zero GX in 2003 and that same year in Japan (and 2004 worldwide) they then release another 2D F-Zero game. What was the market research that led them to this conclusion? Metroid doing alright with a sudden flood of titles? It's disappointing the game tanked but not that surprising either. It's like what killed Rock Band / Guitar Hero. Sudden oversaturation. Incredibly, Nintendo allowed a THIRD GBA F-Zero game to be made but F-Zero Climax only stayed in Japan ensuring it would be the most dismal selling of them all. (But maybe we'll see it ported on the GBA NSO yet!).
I sort of feel like I've become a big, if not THE, F-Zero guy on these forums over the years because of my love for GX and commenting on the series a lot. But it's not even in my top ten favorite Nintendo series. (Although not having had new entries for over 15 some years no doubt assists in keeping it down my personal list). But the reason I'm so passionate about wanting another entry is basically because of my love for one game in the series and that is the GX GameCube game. It's possible this is a StarFox situation. Most people feel that series peaked with StarFox 64 and has been unable to figure out what to do since then. Perhaps it is the same with GX and that will be the high point of the series with no where else to go but I keep hoping it isn't. Mario Kart keeps going and while there can be some new features added in here and there to advance it, the main thing is that it has new courses to race on. To me, that's all F-Zero needs. Even if it keeps coping the GX formula, I'm just looking for new tracks to race on. It can't be that hard to come up with that aspect, can it?
F-Zero X is alright but it is a bit rough compared to GX so it's been harder for me to care as much about it. F-Zero SNES is about the only 2D F-Zero title I'll still play around with but I've also never owned a copy of F-Zero GP Legend to judge it accurately. My problem with F-Zero SNES is how it basic it feels. There's no 2 player mode. It's just the 4 racers to choose from. You've got three Cups to race in and that's about it. It's launch title / early SNES development days are apparant. And yet, I'd still choose to play that game over Super Mario Kart. SMK just feels wrong and obsolete now to me. F-Zero SNES still has a bit of the feel of its later entries and its speed and precision angling still give you that F-Zero vibe. There was a time when I was waiting for Mop it up to join me for an NSO SNES game session and she was surprised to see me play F-Zero SNES while killing time waiting for her. She didn't think anyone was still interested in played that game. Perhaps just by doing that, I really am the biggest F-Zero fan on these forums.