most people can't time the market consistently over long periods of time.
While I (mostly) agree with your post, you raise some interesting ideas for discussion. So many statements like the above have been repeated so often that we accept them as fact. But I'm not sure they are the "givens" that many people make them.
I think the market is generally efficient but that does not mean the efficiency is perfect. I also tend to think that timing works over some time periods, mostly medium term. But that does not mean I believe it is effective enough to add more than modestly to returns.
It was fairly obvious to me in September that the market had gone up really fast and we were facing major uncertainty toward the end of the year over the fiscal cliff. So, I made some major stock sales. This was partly driven by a desire to shift asset allocation but I most certainly accelerated when I did it for timing purposes and I noted that publicly here. That timing save me about 1000 Dow points.
I agree that in general a one month period is way too short to matter and I also agree that reducing fees is one of the most critically important things any investor should focus on. But I have personally benefited over the years by making a few timing moves - but these are infrequent, about 3 major ones in the last dozen or do years.