Reading in the other threads I didn’t see anything (yet) about the difference in the type of magma at Hawaii and Yellowstone.

Hawaii is a basaltic volcano so it has a higher density and melts at a higher temperature (1200 C). This makes it very “flow-y”, or less viscous. While Yellowstone is silicic, melting at a lower temperature (700-1000C) and is very thicc and doesn’t flow.

Think of the difference between water flowing and syrup, that is a difference in viscosity. Things that are hotter flow more easily, think of syrup straight from the refrigerator versus syrup that has been heated. Yellowstone magma is much stickier so it holds much more pressure.

It won’t flow because it is more viscous so it just builds up pressure for years and years until it pops.