When you have a successful business, competitors will spring up to try and take a bite out of it.
Two of them, Jackson-Hewitt and Liberty were both founded by an ex HRB exec, John Hewitt. There are also the do-it-yourselfers that have also taken a bite as well as non-profit volunteers and the IRS itself who will now assist with returns up to what? $60K, or so.
The report says that the loss was mostly in the early part of the season with most of the decline coming in 1040EZ and EITC returns. A large part of this may be due to Liberty's spanish speaking offices "Siempre" and to the demise of the instant refund programs.
All companies eventually reach a peak and then decline and level off at some point. What is so remarkable about HRB is that it took so long for it to happen to them, over 60 years, but that is probably due to the lack of any meaningful competition for so long.
Some of the layoffs in recent years may be due to overstaffing that happens when you are successful.