So, you would like to discuss fuel economy...? Scroll back to 1973, it started then, and we still try. Maybe you were born after that year... You want to save fuel to a maximum, so let us do it this way - Airplane with 300 seats, no schedules, departure when the 300 seats are filled... full airplanes as a rule, no empty seats. Cargo airplanes only cleared to go when loaded to MZFW...
It wasn't long ago (1989sih) that I saw an Aeroflot doing the same thing in Anchorage. When asked why they were parked so long, the local rep quite frankly responded, "...not full..."
Otherwise, you're right about "...
"personally, I like to...", One reason that comes to mind for why this happens, may the absence of more defined SOP guidance. Obviously, there's only so much you can write in an SOP before it becomes too restrictive. I suppose that's one of the reasons why they all contain a clause to the effect of, "...good judgment and airmanship shall prevail..."
Overall, you're right about this; in that we seem to be constantly trying to "Reinvent the wheel". As you indicated, we're been chasing this fuel saving ghost for decades.
Two problems that tend to come back to haunt us are;
One, the equipment changes, thus we are forced to redefine "Fuel Savings".
And two - I think the greater problem - the fuel price changes. When the price goes through the barn roof, it's only then that we climb back on the fuel saving horse again. Basically, I guess everyone becomes complacent until we're bitten once again.
Fortunately, I've got more years in this circus show, than I have left in it. Maybe they'll sort it out before my days of over. I doubt it, so save a rockin' chair for me and we'll share the laughs.
In an ideal operation, a tug to and from the terminal to the runway would save tons of fuel and money. Imagine the number tugs and labor, not to mention ATC communications and coordination required accomplishing this feat in say JFK or ORD, or even LHR would be high too. Would airport authorities want to design and construct special "TUG ROUTES" to help accomplish this means of fuel conservation and the added bonus of helping the local ecology?
Like I said, it's all about compromise.