Love the faux altruism. Not about you, sure. So your complaint is that even after using daddy's credit card you still didn't get a higher league rating than those who spent nothing? I don't even understand your complaint.
With so many variables in this event, coaches, players, etc. it was easy to get distracted by all the shiny prizes and lose sight of the goal. That is by design. It forces each player to choose a strategy based on their individual needs and wants. Unfortunately, you chased/chose a strategy that will now leave you short on the main prize, now needing diamonds if you want it all.
If you chose players based on what they offered as prizes or DS%, not how many yards per football each player ran, then you'll end up short of the upgrades needed for a level 9 OT. However, along the way you got more valuable prizes. You also needed to choose the 'Progress Coach' or diamond coach in order to get the full yardage needed to get the full number of touchdowns required for all those upgrades.
If you chose any other combination, you traded yardage/touchdowns for something else. Doing so got you all that 'something else', but you'll fall short of all the upgrades needed to max out the OT. I, on the other hand, will get a maxed out Olympic Treasury for free, but I got crappy prizes from the players along the way. Medals, blueprints, units, boosts and fragments, I don't need or won't use. A whole bunch of 'who cares' AD fodder in exchange for a level 9 OT.
It sounds like you went for a bunch of great prizes along the way, but will now fall short of a level 9 OT because of it. Sorry you now have buyer's remorse. I guess you'll know for next year and the next event.