Tax services actually do need capital
you need to hire workers
You cant really charge more than $100 to do someones taxes and it taxes a few hours of preparation with a client and an hour or 2 to do the taxes on the computer.
You also have to compete with people like myself who do it for free (I had to pay $50 for the software)
And then you have to make all your money for the year in 2-3 months or so and work nonstop during that time