some bro science below, but...
Presumably grip is needed for acceleration.
At one end you'd have an almost solid tyre that hardly deforms as it bounces over the imperfections on the road surface. For something like an indoor velodrome track then this works pretty well as you lose very little energy bumping over things. But you'd waste plenty by bouncing around on a gravel path, not to mention sliding out as the tyre fails to hold on.
Then as you get a wider tyre and a lower pressure then you can deform around/deal with the imperfections of the road surface. And the ideal tyre depends on the road surface.
And the added reassurance of a tyre feeling more sure footed will lead to a rider pushing a bit more than they might on a rock solid tyre on sketchy ground. So there'll be a crossover where a technically faster tyre probably ends up slower in the hands of 99% of riders/drivers who value the confidence inspired by the marginally slower tyre.