Most polls I've seen tend to suggest that (a) most people's opinions are largely the same as they were 2 years ago, but that (b) there has been a slight drift in favour of remain -- or more generally in favour of a second referendum -- in the last year or so.
The thing that Leavers probably ought to concede is that even a very slight drift is still enough to swing the vote entirely the other way. This is the problem with referendums in general, and close referendums in particular: the winner in a 52-48 result can't really claim a truly decisive win. I wouldn't be surprised if, were the referendum to have been held just one week earlier, it would have been something like 51-49 in favour of remain.
That's clearly only speculation on my part but nevertheless the truth is that public opinion is virtually split down the middle on the issue, and has been for a long time. In such a situation it's frankly ludicrous to expect either side to give up the struggle for their cause and to back the other lot wholeheartedly. If we are to continue pursuing this policy, then the onus is on Brexiters to deliver the successful Brexit they claim is possible, rather than to rely on Remainers to do it for them -- and certainly they shouldn't be exactly surprised if Remainers don't deliver the Brexit they wanted.
Or, in short: if you really want me to back this -- as if my support makes a ha'pennorth of difference anyway -- stop telling me that I should back it and start telling me *why*. Sell your vision. Deliver it. Prove me wrong.