Is it not as much to do with the consistency of dog shit these days as it is to do with tyre size/pressure?
Way back in the 1970’s (and doubtless for years before that) it was all hard, white chalky stuff, not this sticky / runny slop it is these days. That change has oft-been linked to the diet of dogs back then; with a greater consumption of bones (pre-BSE scares) and the consequential uptake of calcium, as compared to today’s ‘complete’ foods.
That sticky slop goes everywhere – I can’t imagine that the white chalky stuff would have been anywhere near as likely to form that weaponized aerosol spray-chunks you get from it these days.
(The diet change / availability of specific companion-animal feeds is also linked to the apparent proportionate increase in cats suffering with gingivitis, and other poor dental hygiene …).