The Leave campaign didn't promise anything tangible beyond regaining sovereignty. Everything that followed is a political decision by the UK government. This has nothing to do with remainers impeding implementation. We were set on a course for a hard brexit by May - she was explicit in the Lancaster House speech and strongly implicit with her (derided) Brexit means Brexit. It doesn't really matter if this was Tory party management or if she believed it or not - the UK was going to leave the EU and its four "freedoms" and likely would have done so much earlier if the ERG wasn't being played by UKIP and the ambition of the current bunch of lightweights drawing a ministerial salary.
What is annoying for those of us in the real world is the predictability of the current outcomes and the lack of any meaningful planning. As an example you can argue that firms who relied on outsourced EU truck drivers using PSC structures should have known that there might be a teensy bit of disruption and planned accordingly but my view - UK Gov had sight of the numbers and could have/should have worked with the RHA to address and mitigate the risk at a national level - stuff like increasing training opportunities.. I guess it was an ideological choice to sit on their hands and let the market react but they were elected to follow this course.
As a country we are going to have to get used to lots of Brexit consequences being managed after the effect rather than anticipated and proactively managed at a UK Gov level. The best firms will be on top of this and been doing this anyway, Lots of others will complain loudly and likely be ignored by Johnson as he knows and expects that they will fix it somehow.