[tidepod12]

You say "strung along", I say "they were willing to give OP a chance at the job even though OP was not fully qualified for it, and when it was decided that the role was no longer available to OP, they told OP that rather than having OP waste their time giving a pointless presentation that wouldn't have changed anything".

[throwaway2245]

I say "They asked OP to do a bunch of wasted work on the off-chance that their prize candidate was not available - even though they were not (under no circumstances) interested in considering the OP against the prize candidate"

There's a simple and known solution to not have to do this - which is to conduct fleets of interviews at the same time, so that you can fairly and accurately compare the candidates.