Airfare Logic - an oxymoron if ever there was one!

I have traveled a lot.  To those of you who read this blog occasionally, that should not come as a shock.  So why am I stating the obvious?  Only to emphasize this next point;  As much as I fly, and as many times as I have to make and change airline reservations, I am no closer to understanding the enigma of the airfare pricing model than I was the first time I stepped on a plane.  It is a complete mystery to me and it ain't gettin' any clearer. 

Case in point.  I am flying next week to Europe on Delta; Minneapolis to Prague via Paris, and returning Dusseldorf to Minneapolis via Amsterdam.  Simple enough, I suppose.  The original airfare was just over $2000.   However, a little digging about turned up a cheaper option.  If I were to spend the night in Amsterdam and fly back home the next day, the fare was only $1000 - half the price, and all I had to do was kill some time in Amsterdam...(its a tough job, I know...).  Even after adding in a hotel and some meals and taxis I was still saving the company over $600.  But this is not the part I fail to understand. 

I know that airlines, hotels, and even tourism boards have some agreements in which they try to make a longer stay more attractive.  I get that. What I don't get is this:  I tried a few moments ago to eliminate one leg of my flight home.  I could drop the Dusseldorf to Amsterdam leg, instead taking a train to Amsterdam from Belgium.  I would still be on the same flight back to America.  I would still be at the same hotel in Amsterdam.  The only difference to the airline is they would be able to sell my now vacant seat from Dusseldorf to Amsterdam to someone else.  They could even charge me the same $1000 airfare and everyone would win, right?  Well, apparently not.  Dropping that one leg off of the flight adds $700 to my airfare and I am not willing to pay it.  So now, thanks to whatever f'd up algorithm Delta is using to compute pricing, they miss an opportunity to increase revenue, Eurail misses a fare opportunity, and I will ride 3 hours in a car back to Dusseldorf just to hop on a plane the next day and fly back almost to where I started from. 

From "win-win" to "lose-lose".  Nice job guys!