Before the referendum, brexiters said no vote would lead to a lot of good things, remainers said it would lead to a lot of bad things. So far it looks like the remainers are right - lots of bad things happening, not a lot of good things.
Other than everyone knowing a lot more about the facts and reality of brexit, what would you possibly expect "new" to happen that would justify running a vote?
I'm not saying that any of this means there definitely should be another referendum, but I'm unclear why you think we definitely shouldn't. The amount of time and money that has been spent seems a reasonable response to the initial referendum, and it seems to me that everyone is a lot clearer on the options available.
If the leave side are confident in their case, then there is nothing for them to fear from a referendum. If anything, it would provide better bargaining power to the UK against the EU, and for leave politicians versus the remainers. As it is, it just looks like leave have a weak case.
It also seems to me that the reason the EU is difficult to leave is because it's a pretty good deal for its members. The UK has already negotiated all sorts of opt-outs and exceptions, it doesn't seem unreasonable for the EU to impose some conditions. The alternative is that the EU itself falls apart. Maybe what some people want, but not really what I think would be good for Europe.