10w30 grades "typically" start with a thicker base oil, thus requiring less in the way of viscosity improvers to achieve the 30 grade at temp. So, hypothetically, a 10w30 "should" be more resistant to shearing, and "possibly" have lower NOACK numbers...
Except with synthetics, some base oils can meet, or come very close to meeting, the 5w30 criteria with very little, or, as rumoured in a couple of boutique brands, NO viscosity improvers added at all...
And...10w30 is almost never spec'd for any new car, and some brands don't even blend a 10w30 in some lines, so don't be surprised to see it disappear soon...