I've always experienced the opposite, they jump into the fast lane and go like 5 under the speed limit, I notice less Prius doing that now and more teslas though

Do you know how fast a Prius would have to be driving to get mileage levels close to a non-hybrid?

Geez, as someone who has owned almost nothing but Priuses, "all" is a pretty glaringly wrong claim. I typically despise going past the speed limit (especially on freeways), much to the rage of other drivers. If it matters, this has always been my driving style since before getting into them.