The caves aligning with the grid was only a thing so that the GM could describe the layout and the players map it with a pencil. Now, a lot of people use a VTT and the GM provides the map digitally and the players can get it shown in real time or over the net. So there is less reason to make the cave walls align with a grid. Also, if you are wanting the map for a VTT then the app can put the grid on itself therefore its better to have it without the grid already on it.

So in short I think yes there is plenty of demand for realistic maps without the grid.