They showed off Feature Service tiling at Dev Conf. That is why Hosted Layers are so fast.
They said it "might" be in 10.7.1. I can't figure out how to publish a tiled feature layer from Pro. Can anyone say if this made it to the shipping 10.7.1 Enterprise? If so where can I read up on it in Documentation? Thanks!
This is the sole reason I pushed for Portal. Dynamic map image layers slow down after more than a few users at once on a heavy layer. Feature layers themselves have never been fast enough to use for polygons or lines. WebGL layers have also not worked due to the WebWorker bug/limit. I am greatly looking forward to feature layer tiling as the solution to build performant sites with high traffic.