If you've used Lucario as much as I have, you should know that it is much MUCH better than you're giving it credit for, and that it has a very easy time setting up. Also, you are most definitely theorymoning since you aren't actually providing calcs for the damages you're mentioning. Bullet Punch from Scizor does hurt, but it isn't even kind of a way for you to count on beating Lucario, as Banded Bullet Punch does between 38-45% to Lucario, which leaves you with about half health after Rocks and Life Orb. But then what? If you were relying on Scizor to revenge Lucario, then your team can't handle the remaining turns Lucario has to beat you. Plus, lets say you think Lucario is going to SD so you switch into Scizor, but actually it just goes straight for the Close Combat. You just took 72.88 - 85.71%, and Lucario can now guaranteed kill you with a non-boosted Extremespeed (16.03 - 19.24%, which at minimum is 100% assuming Rocks 12%+72%+16%=100%).
Also, the way you talk about using Lucario is, in my opinion, wrong. Lucario shoudl be paired with something like Celebi or Espeon, which can BP as Tyranitar/Scizor Pursuits, thus giving him the +1 boost from Justified, and another from Swords Dance
or simply attack the switchin with an insanely powerful Close Combat at +2 (or even at +0 assuming you didn't BP in Lucario). Honestly, everyone should be using the Bullet Punch+Extremespeed set, in my opinion. It demolishes offensive teams as seen in
this battle I always show people when they doubt Lucario.
That is how you're supposed to sweep with Lucario. I'm not even sure where I want Lucario, as I can see him easily being B+ or A-, but I just want to make sure people understand how amazing he is in practice.