Actually no it isn't. If you know what your doing it can make you rich. I got my Anaconda months ago, turned it in to a Hauler when i got it, on a round trip today it makes me one million (400 cargo space - 19 ly distance), 4-5 million in one hour and that has now made me stinking rich and i have managed to get A6 mods all over.
It is a myth that you are broke for a long time after purchasing an Anaconda, for a short time maybe. People say that to stop others going for Anacondas (or they dont know what they are talking about). It all comes down to knowing what to do with it when you get it. Fact is i found it to be the opposite and most people i know who had Anacondas for many months are the ones with big bank accounts.
The only time it gets expensive for me is when you get hull damage and have to repair, that can be in the millions. Example 55% damage to my hull got me an 8 million bill.