Aggregate job creation and destruction (quarterly), or is creative destruction slowing down?

Is the U.S. labor market becoming less dynamic?  Here is much more (hat tip to Mark Thoma, but from John Haltiwanger, paper here, slides here), and an excerpt from the FT:

Yet there’s obviously a meaningful secular story as well, but it’s more complicated and, indeed, remains something of a mystery, as Haltiwanger can only posit a few educated guesses.

Among them are the increasing share of US employment moving to businesses six years or older; the shift to large-scale retail chains; the aging of the US labour force (and therefore less willingness to experiment); declining job creation rates for startups; economic uncertainty; policy uncertainty.