Trying to "force the airplane off the ground" by rotating prior to Vr has a few safety downsides. One of them is that it makes tailstrikes more likely, as you'l

Trying to "force the airplane off the ground" by rotating prior to Vr has a few safety downsides. One of them is that it makes tailstrikes more likely, as you'll have to carefully moderate the angle before lift occurs. Another is that it removes loading from the wheels more quickly, which extends the "awkward zone" in which the airplane is still rolling on the ground but has so little weight on the wheels that it will skid very easily. This can lead to aircraft being blown sideways off the runway since you can't yet roll into the wind. A somewhat less direct concern but a related one is ground effect lift. the aircraft can remain a short distance off the ground (roughly a wingspan of altitude) at lower speeds than it can actually "fly," due to ground effect. Smaller aircraft might routinely spend some time in ground effect gaining additional speed before they begin climbing, but airliners have so much thrust they usually rotate pretty directly to their climb speed. This makes it more of an issue though that if rotation occurs too far before Vy climb speed the ground effect period will be prolonged and increase the amount of time the aircraft spends at risk, flying but slow with poor control authority and too close to the ground to have much of a recovery opportunity. The ground is a pretty safe place to be, the sky is a pretty safe place to be, but that first couple thousand feet between the ground and the sky is rather hazardous and jetliners get out of it as quickly as possible.