Even Dominic Cummings said at one point there was a strong case for a second referendum to decide what form Brexit should take (note NOT a re-run of the first referendum).
Not just Dominic Cummings[0] but also Jacob Rees-Mogg[1].
I think it would have been democratically unconscionable to not have had "No Brexit" as an option on a second referendum, but that would have required a relatively complicated ranked voting system, and arguably it would have made more sense for the first referendum to have been set up that way instead.
I suppose the alternative would have been for Remainers to boycott the hypothetical second referendum, and hope that the number of votes for the different Brexit options summed to substantially less than the number of votes for Brexit in the initial referendum.
[0] https://www.markpack.org.uk/150719/dominic-cummings-second-r...
[1] https://metro.co.uk/video/jacob-rees-mogg-suggests-holding-s...
Yes that was more or less an explicit choice from Cameron IIRC - if we come up with a plan for what happens afterwards, that plan may reassure people that Brexit can work out OK, and play to the other side.
So no plan. Genius.
It was clearly reckless to hold a vote on something without a plan on how it was actually to be implemented or even what it might look like; and there were calls for the government to do some investigation here and publish a report or some such document - the decision not to do so was in order to sow that uncertainty.