Nemesis tanked at the box office for a number of reasons. It had a bad release date pitted against two of the biggest movies of the year.
That doesn't really hold water when you consider that earlier Trek
films held their own against juggernaut competition (Wrath of Khan
opened a week before E.T.
in 1982; Search for Spock
was sandwiched between the releases of Indiana Jones and the Temple of Doom
in 1984). Blaming the failure of Nemesis
on Harry Potter and LOTR (plus there was a James Bond film, too!) is weak tea. It failed because it sucked balls and not even Trekkies wanted to see it after the first weekend.