In making an Economic Decision, one must consider the available Resources & make the best out of it.The 4 Resources consist of Land, labor, Capital & Enterpreneur as stated in all the Economics Books seemed to be outdated without the "TIME" factor .E.g. 1.You have capital to invest in a specific industy (say to obtain a license & location) before potential competitors get in. If you don't make it on the TIME, you will lose your capital investment. 2. You have a capital (fund) to take advantage on undervalued stocks/property due to forced-selling rules (by banks etc). If you do not plan on the "right time" to purchase, you'll fail to make profit while "wrong timing" will ended you up with losses.3. & so much more on "time" factor!

why PERT and CRT and other tools are avilable -- this will give you what you want.

Hmm......not sure about this but labor means work. In the examples you have listed, part of the work (aka labor) is to figure out the optimal time to invest. Thus, I think the 4 resources cover everything including time.

The factors of production contribute to making things. Having all the time in the world, by itself will get you nowhere.