Your making an argument for something no one is arguing for.
How many people with a 318 on this site are even asking to do a 12 seconds, most just want cam 4bbl maybe headers, some want the next step cr and some form of head work or better heads. Highly doubt that a lot of 318 owners on here are expecting faster than a 13 second car most would be happy with a 14 second car. Bet most 340/360 owner aren't even looking for 12's.
You don't think a set of aftermarket heads like speedmaster, eddies or even trick flows with 10.5:1 high lift 235 ish cam air gap 750 headers in a 0.030-0.060" over bored 318 with 3500-4500 + stall and 3.91-4.88 gears is gonna be a dud??? Yes a 340/360/408 built the same may be better but so would a 440-543 over that there's always someone gonna be better out there unless you have the best and fastest car out there?? Just cause you think it's stupid to give up some power by going 318 over 340/360 someone thinks it's dumb for even running a small block in the first place. A some will think it's dumb for running Mopar since Chev LS have all the goodies made for them etc..
And if you want to see high 11 second and faster 318's go on the Dakota forums. Or Australia they don't have a lot of 360 kicking around from what I hear.