Why doesn’t Starlink support the eastern US?

https://www.starlink.com/map

My family lives in rural NC outside Raleigh and can only get DSL. I’ve been trying to use coscreen and other tools to help my mom but the experience is obviously garbage. They can’t really use FaceTime or zoom, or other tools. I ask every now and then “why don’t you use Starlink,” which is what they used when they lived in rural California outside Yosemite, and they say it’s not available. Today I was doubtful so I looked it up and was stunned to see a very clear carve out for the eastern United States from around Houston to Wichita to the coast as the only part of the world that is waitlisted. They could get service on Machu Picchu but not outside Raleigh.

What gives?