What not only I have noticed: almost all stories of utopian places end with them having perished or disappeared in some other way. Or the maps have been lost, so that one can no longer find the way to the location of a utopian story.
I have created a collection of utopian places - sorted according to the categories of cities, countries, islands and planets - and transferred them to a signpost, the shape of which is based on post pillars, quarter and half hour pillar distances: In 1694, all important postal and trade routes in Saxony had these Electoral Saxon post mile pillars erected for this purpose to indicate official distances and uniform calculation of postage. These signposts did not indicate distances but the time it took to get from one place to another, a time-efficient system to organise the transport speed of messages and goods. This meant that postmen or messengers could reach their destination more quickly, but were also less likely to be late.