I just played a good game that will prove my targetman point.
Now, before the game Eddie Johnson was hurt, he started the game at 78 fitness. I played him just because I didn't have any other good TM to play and hoped he could manage a few goals before I could take him out and defend.
After 37 minutes, Arsenal had 20 shots and 4 goals. Eddie Johnson was rated a 5 and was now at 60 fitness. Obviously, my idea failed and he was doing horrible. My whole team, espically my defense, was struggling from not having a targetman that could attack the opponent and keep them on the back foot.
So at 37 minutes, I switched Johnson with Benjani, who is at 15 heading and 15 jumping... decent TM, but not good enough on most cases. From then on, we managed to control the game and came back to 4-4 around the 80th minute. Had I wanted a draw, I could have gotten it, even though I chose to go for the win and it backfired. Arsenal had 6 shots in ~60 minutes and were outscored 4-1 because my targetman could do his job.
And this is why these tactics struggle in lower leagues -- the targetman aren't up to par to the point where they can control a game. A good targetman will win the game for you.