The idea was lots of people could file for free using a private online service. Not many people at all ended up using it, since it wasn't in the company's interest to have people not pay them.
Related: TurboTax Deliberately Hid Its Free File Page From Search Engines
https://www.propublica.org/article/turbotax-deliberately-hid...
HN discussion: https://news.ycombinator.com/item?id=19758126