Here’s a good example of how switching to static on a high traffic website makes it 10 times faster:
You’ll find other high traffic static websites like SketchApp or ICIJ (Panama Papers) on https://www.thenewdynamic.org/showcase/
Static sites are way faster, because you don’t depend on real-time queries on a database. Content is cached and ready to be served.
When it comes a static site hosting the generator itself does not matter very much (except if you build every 2 minutes), as it’s the result of the build who is served to everyone. So it’s mostly about the network latency, the CDN and the front-end code quality, e.g. whether or not you provide a good performance (and go full PWA that you can check with Lighhouse. That’s what the Washington post did, one of the top 50 US websites., even if it’s not entirely static.