In the regular season? As in... not playing a playoff caliber team every single game. Not having the offensive burden of teams crafting specific plans to shut the opposition down. Many of the greatest players of all-time, even all-time great playoff performers, have had their production slip in the playoffs when compared to the regular season.
Beyond that, under Ken Hitchcock, David Backes has always been used as a defense first player. Ignoring that aspect of his game, which was fantastic in the playoffs, and narrowly focusing in on a small decline of offensive output isn't weighing the situation correctly.
All that being said, your opinion is your opinion. I just don't agree!