I have not seen PB pipe used only for the main supply before, especially not going into the ground. It only comes in from the meter about 25 feet under the house, then connects to copper distribution.
Does the larger pb have the same issues? I don’t see why it wouldn’t, but at least there is less of it and only a couple of fittings.
I have never seen a PB main either, but that is what you have, I would right it up as a potential issue both due to the fittings issue (not too much of a problem with that system) but also because Chlorinated water leaches out the plastic from the inside leaving the piping very brittle.
PB main water service is very common in the areas that I cover. Yes, the blue PB pipe has the same problems as other gray PB pipe typically found in interior plumbing.
I have inspected some homes where the blue pipe is not visible, the only indicator is the gray 90 degree plastic elbow connected to the internal copper pipe at the foundation wall.