This has a lot to do with what phases the projects were in at the time. Rat and Marvel were already in the final phases of construction and it would have been too late to shutter either construction site. There's probably a good chance that MMRR could see a similar shutdown to Tron once the enclosure is complete. I haven't really heard much about the current status of MMRR. "Pacing" construction the way you describe would not make sense. It would lengthen the stay of construction crews and lessen productivity resulting in higher payroll. I know corporate finances seem pretty strange, but putting a pause on construction is the most logical thing they could have done right now to help with finances and crowds. Again, while Walt Disney World itself might be generating a profit, a very small profit compared to what it usually generates, the Parks division as a whole is losing a LOT of money. By not spending on Tron right now, their losses lessen by several million. Seeing how opening Tron won't create an immediate return on investment and drive addition profit in this current world, it's better to lessen the losses in a time of hardship and wait to spend profit in a time of prosperity.