Is it merely the lack of our knowledge why stable traversable wormholes have not yet been invented to allow for instant travel between remote locations? Are we just not that advanced yet? Or does such a thing break some known laws of physics and therefore cannot be built in principle?
Let me write a bit of sci-fi here just to clearly outline what thing this question is about. This wormhole, as a mass product taking any and all means of conventional transport out of business, is manufactured looking literally like a pair of window frames (or doors, gates etc.) tied to each other by their face sides. Upon unpacking this product, the two gates (Gate 1 and 2) can be just taken apart and placed at any distance from each other. Whatever enters Gate 1 through its side A will not emerge out of its side B. Instead, it will emerge out of side A of Gate 2, wherever that is now. Similarly, entering side B of Gate 1 will just let the object out of side B of Gate 2.
Gate 1 will be installed at say "London International Teleport", Gate 2 will be transported (initially by conventional transport)ⁱ to wherever it needs to be at, say "New York International Teleport". Wealthy individuals will be able to install such gates at their homes so that getting from a mansion in Miami to another one in New Zealand will be just a matter of opening a door and walking through it like it was in the same building.
For simplicity let's assume that both gates are installed at the same altitude so that stepping through them does not involve any work against the gravity of Earth.
Physically, such a gate could work by say keeping two points in our 3D space tied to each other in some other, 4th dimension (like as if we lived in 2D world, on a piece of paper, making such a wormwhole would be just a matter of bending the paper and affixing two points on it to each other). But this question does not limit the physical implementation to any particular solution.
ⁱ It is also interesting if transporting such a gate through another gate would not be outlawed by physics.
Closely related, but not the same: