Whether we believe in karma or not, does its theory hold good, irrespective of whether we believe in it or not?
The law of nature is that any system will return to its original state of balance, unless a new force holds it at a different level. If and when this force is removed, the system will return to its original state. If an outside influence happens, that new influence will lead nature to a new state and the process will begin again.
Therefore what goes around comes around is as a one-on-one effect, (not ever) Karma in itself isn’t that simple. There will always be outside influences at one or more other point in time, therefore balance will eventually be restored, but by a counteracting force. It is that counteracting force that can happen at any time that we have no control over that changes how the initial deed and karma is enforced.
Unfortunately, not everything that happens by nature is visible to human intelligence and consciousness. It is because of this that it is difficult to know whether everything returns to its original state. Some parts are visible and recognisable through our own response to our emotions and thoughts, but it may be that some actions return to us as reactions further down the line.
I believe that what goes around comes around, will come around and restore the balance or equilibrium, subject to new modifications due to outside influences, which unfortunately are not always in our control and not in the form we expect or anticipate. Karma will happen, but not always in the form we anticipate.
Therefore, we must put our trust in karma and the universe that it will work its magic to restore balance, but it’s something we must wait for patiently.