First of all, the logic of your sentence is twisted - labor costs for the firm rise - but so does productivity, only more.

The chart I showed is one of many available on this subject. Just google "productivity and wages gap". This disconnect of wages from productivity has been well known for years. The first publication, I believe, was from the Economic Policy Institute. Some conservative think tanks have challenged it, strictly on the basis of a different CPI or a different calculation of total compensation rather than wages, but no matter what adjustments are made the "compensation" growth curve never rises to the level of productivity growth.