If you have that mentality, go shoot the 70-200 f4L IS. No one will be able to tell the difference between the 2.8.
Most people couldn't tell the difference between f 2.8 and f4. Getting to the difference between f2 and f4 then we are getting into an area where I would hope most on here could, so no, if narrow dof is what you are trying to achieve then f4 is not particularly effective.
You seem to take offense not at the content, which is well backed up with maths, but at the contrary message. This is a forum, a place for ideas, nothing you have put forward supports your opinion, you can't point to an image, anywhere, that is unmistakeably shot with a 135 f2, that is not confrontational, it is just the truth. Don't forget I have a 135 f2 and used it for years, though all on film, I now have the 100 IS macro and know I couldn't tell the difference.
The 85 f1.2 does the narrow dof field well for two reasons, it is fast, obviously, but because it is a medium focal length you automatically move closer for the same framing, this also narrows your dof even more, however when comparing the 135 f2 and the 100 f2.8 the tables turn, you stand closer to frame the same for the slower lens, because you are closer your dof is less, seriously, we are talking 1" difference in dof on a wide open portrait from the two lenses.
If your buisness model is based on ultra narrow dof and you are getting lots of buisness then obviously the $5,000 more expensive 200 f2 makes sense, if you are anybody else the difference between a 135mm image shot at f2 and a same framed 100mm image shot at f2.8, well, that 1" dof difference is marginal at best.
My clients don't care between f/2 or f/4. That's my job and If I can see the benefit for f/2 I will use it.