Id say the 787 is a failure for the reason that it does not look like Boeing will recuperate the investment capital put into thw development of the 787 (only after 1,100 are sold is Boeing expected to make a profit on the program). That to me regardless of order amounts are a failure.
My criteria for sucfess goes like this
Failure- unable to break even on the aircraft
Minor success- break even or a minor amount of total capital gained
Major succes- Large amount of captial gained
By following that criteria the failures are 787, 748’ A380
Minor successes- A330neo (as of current order standings), 777X (as of current order standings)
Major successes- A350, A330ceo, A320ceo, A320neo, 777, 737 NG, 737 Maxes,