The difference between the 911 and the Versys is that the limits of the 911 are very much defined by the vehicle itself. Tires, brakes, suspension, etc all work together to define its limit. Different drivers can get it closer to or farther from its limit without pushing it over the limit, but largely the limit is the same.
On the bike, the limit is mostly up to you. Yes, tires, brakes, suspension, all the same stuff that play a role in the car play a role on the bike, and the bike does have an absolute limit that it cannot go past, but you're deciding how far the bike is leaned over, where you are on the bike and what you're doing to affect traction while leaned over, which is another way to say that the limit changes, largely depending on what you're doing.
In general, the bike will let you know when its at its limit, the problem is recognizing the message, knowing what to do with it, and reacting in time. You have very little time to react once the bike tells you you're going too far.
The other problem is that many ways to save the bike from going down are counter-intuitive. For instance, a tank slapper
, your brain will be telling you to get on the brakes and slow the F down. What you really need to do is take weight off the front tire, i.e. get on the throttle hard. Very counterintuitive.
When the front end washes out, your brain will again be telling you to get on the brakes, and grip the bars so you can try to right the bike. Most of the time, what you need to to is relax, dont white-knuckle the bars, and let the tire do its thing, and it will recover.
There is much reading to be done on this subject, and if you're truly interested in understanding how to ride at the absolute limit of traction, it would do you well to understand all the theories of how to ride and how a bike handles at the limit.