Think about when we learn to ride a bike, or teach a child to ride a bike. One of the key things is them cycling at a good enough speed for the gyroscopic effect to make it all easy for them, rather than the whole struggling for balance and trying to correct with steering.
That's a circular argument...
Surely it's a valid point - when learning to ride a bike, it is
something to exploit, because the more difficult corrective slower speed skill comes with practice, learning and conditioning.
I'll repeat, a bike - or for that matter, motorcycle - travelling with sufficient speed, wants to (notwithstanding I'm not really
anthropomorphising a motorcycle or bike...) stay largely upright (assuming it's already upright and not at some odd angle or lean). Now true enough, the mass of the rider has a bearing - it just makes that speed a bit higher than an unmanned cycle / motorcycle.
Speed is important because the steering input required to correct a lean is strongly speed-dependent - because centrifugal force varies with v².
To look at it another way, when the bicycle leans to one side, it will continue to fall to that side unless something happens to put the wheels back under the rider's centre of mass. The faster the bike is moving, the smaller the change in steering angle required to accomplish that lateral correction.
Consider a racing motorcycle cornering. Leaning is used to counter the natural forces at play, and assist with and significantly reduce any steering input required. And even with such considerable angles of lean, they're not usually in any danger of falling.
Now true enough, I'm not suggesting that this is purely because of gyroscopic effect - it isn't - inertia becomes a significant factor, but all the same, the faster the speed, the more influence of the gyroscopic effect, and the more relevance of inertia, and very much reduces the need for corrective input for balance.
Point being, though, that with cycles and motorcycles, with a certain speed comes gyroscopic effect, inertia, and a natural tendency to stay upright. That isn't just because of effects of leaning being minimised - that's all chicken / egg - there will be less need to lean, or for that matter, less chance of leaning - it's just as likely there will be minimal lean, because of lack of requirement to do any corrective movements to keep it in balance. The reality is, as the speed increases, gyroscopic effect increases, the effects of inertia increase, much less corrective action is required, or desired, because if it was done, it would probably largely become unstable.
Now the ice thing has some bearing - but when I was talking about friction, I wasn't just thinking of friction between tyre and surface... What I would say, though, is that for a bike, or motorcyle, that suddenly hits a brief patch of ice, but travelling at fairly normal speeds, it doesn't necessarily mean that all balance goes out of the window and a crash ensues. If the bike / motorcycle is travelling straight and true, and the surface suddenly loses a lot of friction, briefly, the bike / motorcycle may well stay upright - it just depends on whether much in the way of corrective action was required (or happened out of panic) whilst on the very slippery surface.
Clearly were the bike / motorcycle cornering, or truly having to correct much lean - then true enough, a crash almost a certainty - but running straight and true, at a normal speed, and suddenly loses grip briefly? Not necessarily