Given the relatively labour intensive nature of the services sector, the scope for rises in productivity may be more limited than in other parts of the economy. So the outperformance of services may presage permanently weaker productivity growth.
A second factor that has weighed on productivity is weak business investment. Following a fall of 22% after the financial crisis, it took until 2014 to recover to pre-crisis levels. Weak business investment implies slower growth in capital and hence output per worker.