Well, shouldn't the Modern boats be faster than the Laurin even if sailed "worse"? After all, according to the go fast gurus there is absolutely no comparison in speed between the old boat and the modern boat.....right?
Ignoring the ARC for a sec and getting back to generalities, it is my experience, sailing both classic and modern displacement racing yachts, that there very little comparison in speed between the old boat and the modern boat of similar size - because the physics doesn't change
. There's perhaps 1kt in it, but not much more. In fact, taking it to the extreme, in some conditions (eg. very light winds) some old designs can be significantly faster than a modern design due to greater SA/D and greater momentum.
Design rules have changed several times since the 1880's (roughly when gentlemen's yacht racing became a popular sport) and, each time the rules were tweaked to improve one aspect or another (eg. safety!) that did not always mean that the newer displacement yacht design was faster through the water than the old.
..more manoeuvrable, yes, more comfortable, perhaps, but always faster? No.