it was axed, for whatever reason
That’s a long and boring story, but it was largely to do with the networks buggering about with schedules. The episodes were shown out of order too, so the story arc made little sense. There’s probably many, many articles about it on that Web.
The first episode aired (“The Train Job”) was shown before the two-parter pilot. It was thrown together at the last minute because Fox wanted an action-centric opener rather than something exposition heavy, and it shows. It’s probably the weakest episode in the series. You really need to watch them in order; the running order on the disc is correct.
Despite all that, it’s not the case that the show wasn’t popular at the time. It was; problem was, it was very expensive, so had to be very successful to justify its budget.