I tend to think that there haven't been any kernal exploits found in HOS because people really haven't been looking for them. What's the point in even looking if you already have a perfectly good entry point and there's like 15 million exploitable consoles out there anyways? And for anyone who REALLY wants a hacked Lite, V2, or OLED, the mod chips exist. Switch 1 hacking has been nothing but accessible, and accessibility inheritly breeds laziness when it comes to finding exploits. We haven't NEEDED another exploit in the Switch 1, so another one hasn't been found.
The PS4 has been different because after some time passes, getting your hands on a 9.00 firmware PS4 becomes difficult, so every so often, a refresh is necessary due to the overall demand. Even then, there wasn't much movement in the scene since an entry point still did exist on older firmwares.
Considering the Switch 2 doesn't have any real points of entry yet, I tend to believe that an exploit will be found within the first year and a half (remember this is Nintendo we're talking about, their track record with keeping consoles secure is utter garbage). And when an exploit is found, release of it is probably going to be limited until more consoles are out in the wild. Why release an exploit that only applies to 3 million systems, when you could wait and release it when it applies to 10+ million systems?
There's also very little to do on the Switch 2 right now (in terms of games), and there probably won't be much to do on it for at least a year or two, so I imagine that'll also play a major role.