I disagree.
If anything, this will compel the tax preparation software companies to get even better than before, and offer an increased value proposition.
Competition benefits the consumer, and for a long while there's been limited, mostly fixed competition (via Brand awareness mostly).
FreeTaxUSA is amazing, and cheap, but it does not yet have the brand power the incumbents do.
It's unlikely the IRS offering will be as easy to use or as pleasant as the existing offerings, but it will be a huge shot across all of their collective bows.
Keep in mind the IRS offering a free online service for tax filing does not reduce the complexities of the current tax code - nor does it make for a more fair tax system (one where having means to access professionals reduces your perceived tax liability). This system merely means fewer people need to pay $49 a year to file taxes...