Luck favors the prepared.
Luck has no place in aviation.
Start reading up on short field and unimproved operations and you will understand a little about the 'mindset' of a short field pilot vs one that flies out of 10000 ft runways in turbine equipment.
I flew piston twins for years from rough, remote airstrips, and always ensured my numbers were met. If not, I'd download, fly early or late, or do whatever was required to be legal and safe, and to meet all my numbers...including NOT taking off below Vmc. I also always took the time to calculate my performance on one engine and plan accordingly.
I have felt under these scenarios..getting the plane off the ground, then accelerate past Vmc, in or near ground effect, talkes almost little time...and your there...
If the engine fails in the meanwhile, you'll never get there.
Can't argue that planning VR after Vmc is prudent...but the ops might require short field, or soft field techniques...so the mindset is to understand that sub Vmc engine out, you pull the power back untill the roll tendency goes away, given the appropriate control surface deflections.
You've probably not had the benifit of a genuine assymetrical thrust situation at low speed and low altitiude outside of the training environment, but the notion that you can simply "pull the power back" will quickly go away, if you do. If you're below Vmc at the time, you will be very unpleasantly surprised.