Just because there’s a logical explanation for why it could work doesn’t mean that’s actually what happens, or that pressure is even the dominant effect causing cracks.

Cracks could also come from bouncing around in the water, which could be solved by holding them up in some way. Or it could be weak points/areas from not badly formed shells from hens living in too tight quarters or being malnurished, where buying eggs from more humane sources would solve it. Or a combination, where the pressure differences in the water from rising steam bubbles cause uneven water-pressure on the egg, but they only crack when they are sufficiently weak to begin with, so just putting less water in might be enough to not make em crack (cause then there’s also less water pressure). I could be the packaging, that some eggs develop cracks during transport and they then make them vulnerable, so more local or differently packaged eggs wouldn’t crack at all. As you can see, it’s not that hard to come up with logical explanations and just doing a few things differently might just solve the problem, and even then the reason it was resolved might still be something completely different than we thought.

For comparison: I haven’t poked a hole into an egg in a long time, and I think I had like one or two crack this year. My eggs come from the farmer one street over, and the hens are freeroaming with plenty of space. They don’t get transported at all. Sometimes, I use a steam thingy to boil them, sometimes in water. Even when I did poke holes in, some eggs used to crack anyway, and I’d guess 1 in 3 months in a pretty good guess as to what the frequency was, that’s why I said “roughly the same numer” in another comment.

I stopped doing the “pokey thing” and have had roughly the same number of breaks at before, maybe even less (one less point to fracture from without the hole). Subjective interpretation of the effectiveness is useless, as we humans are subject to so many possible bias that’s it’s impossible to be objective, no matter how hard we try. You can’t even eat enough eggs to have a statistically relevant sample size, let alone one large enough to determine if it does or doesn’t “help a little”.

You “feel” it helps. That’s ok. Also ok to act on. It’s just about boiling your own eggs.

Yes, why? Does that help or shmelp?

Yeah, but then you have to watch your pot for the moment it starts to boil. It’s easier to just boil the water, drop them in and then set a timer.