Do ordinary people (those with a job that deduct taxes, a mortgage, retirement account and basic stuff) need an accountant to prepare their tax returns?
Here in Brazil, if you are required to do a tax return (people with income below a certain threshold, over a certain age and a few other situations aren't required), you use our IRS's software to plug in the numbers for income, dependents and deductions, as well as property that has to be declared (such as houses, investments, etc). It shows you how much taxes you have to pay under each way of filing (simple or detailed) and if you have tax returns to receive. You can then print out a copy for your records, save backups and send the return either online or in a bank with a pendrive.
The only people I know who use an accountant are either business owners, where it is legally required that an account go over the books, or someone with very complex investments. Oh, and doctors and other medical providers, since they have to itemize their income and it is a huge pain.