df1-
If your carrier uses "balanced field" V speeds, (and most do), then you are weight limited for any given set of conditions
for a runway of the same length as the balanced field length. If the runway is longer, you don't increase the V speeds. Now, given the very long runway case, you can increase the weight (and the corresponding V speeds) to make use of it.
Take the case of a takeoff with a 20 knot headwind. The indicated V1 speed wouldn't change (for the purists, it may cahnge a knot or two), but you'd have excess runway (called an "unblanced" condition).
In other words, it's not simply the speeds that limit your takeoff, it's the weight/speed/conditions relationship......and be sure not to confuse "balanced field length" with the available runway.
