Well, there's speed and then there's _speed_. As the OP says, very fast designs today are like the Sail Gran Prix [1] boats, 15m long foiling catamarans that go 3x the speed of the wind, up to around 50 knots.
They bear nothing in common with a typical monohull cruiser, or even racer-cruiser like a J-109[2]. Let alone compared to a comfortable cruiser like a Hallberg-Rassy[3]. These are all displacement hulls, whose speed is fundamentally limited to waterline-length.
There are monohull sailboats that can plane (most dinghys under 20' for example[4]), and there are large catamarans that can go much faster for their size than monohulls[5], but there are many tradeoffs in cost, dockage availability, and (somewhat subjectively) weather comfort.
