This construction practice quite likely was among Ma Bell's standards. I quite fondly recall seeing a few stretches with similar close-arm construction along subscriber leads through the late 60s here in the south-of-Boston vicinity. It is possible the example in this image had something to do with keeping a safe distance from the inherently dangerous, high-voltage, open-circuit voltage of the series street light cable that passed through/beneath the phone openwire in this picture.

Given the multitude of crossarms upon the pole connecting in the background it is quite possible this was a toll lead or predominantly so.