Brexit is a word that seems to have many meanings. Brexit to Brexiteers means a clean break. Brexit to remainers (remoaners?) means the end of a trade regime that Britain was doing fairly well out of despite the large dues. After Brexit, whenever or if ever it happens, Britain will have to sit down with Europe to negotiate trade deals. This is not mentioned by Brexiteers. The complication of the Anglo-Irish Agreement was pooh-poohed by the Brexiteers during the run up to the Referendum of 2016 and now they are hoist on their own petards. I realise that there are many other reasons besides the above.
Brexit to some Brexiteers means what they rather fancifully believe is the 'clean break' of no-deal. To some other Brexiteers, Brexit means continued membership of the customs union, but not the single market. No doubt that there are numerous other configurations of Brexit that various people thought they were voting for, including staying in the single market.
These different Brexits would result in very different futures for the UK, and yet they were all aggregated into one vote, 'Leave'.
There has yet to be any evidence that there is greater support from the public for any particular Brexit than there is to remain.