Well, in F-Zero X and GX, if you press left, the craft goes to the left immediately. If you do the same in Wipeout, it rotates to the left, goes a bit to the right and only much later really goes to the left. In a sense, Wipeout is immediate in the sense that there is a visible reaction to your button press, but it is absolutely not direct when it comes to controlling where the vehicle is going. Even if you like this kind of indirectness, it has serious implications towards the track design and the gameplay, because super quick reactions to the track are not possible, which limits the adrenaline rush and the arcade-style twitch-reaction to situations.
By the way, I did not want to downplay the difficulty of Wipeout with my posting regarding F-Zero. I have played maybe 50 hours total of Wipeout games and have not fully beaten a Wipeout game, it would be unfair to comment on its top difficulty. But no matter how difficult it is, I have played to completions hundreds of games and several hundered more games far enough to be sure of their top difficulty and F-Zero GX is the absolute top of all of them (next to Monkey Ball if you disregard time attack, alone if not), so even if Wipeout managed to be more difficult (which could really only be by a tiny bit), to call F-Zero GX anything but super tough is either a sign of not knowing the game or pretense.
That's why it's more difficult though. The speed ramps up and that momentum shifting stays relevant, so you have to be fully aware of how your vehicle is going to move at insane speeds, with tight ass track designs. It's tough as nails. And there is a shit tonne of super fast twitch reactions - you need to be processing in your head how your ship is doing in the space around it at full blast, overclocking your analysis and fine tuning your inputs like nothing else.
F-Zero in comparison is kind of like those old dodgem toys where you move left and right to dodge incoming vehicles. The physics are super simplified by comparison so that you can focus on sliding left and right... sure it gets fast and hard, and you have to focus on a clean line through the track but...wipeout does that while taking into consideration momentum... that's why it feels like a sim. You're constantly planning ahead not just the track but how your momentum is shifting along it. F-Zero is much more chilled. Still fun, and fast, but your brain isn't melting.
It's like you're sitting in the cockpit, fully responsible for the control of the vehicle. It feels a lot less arcade. I get some people like arcade, I like it too, but there's very little like wipeout.
And if you want to reach immortal speeds, there's Zone mode.