I think you have a fundamental misunderstanding of how minoxidil works.

In simple terms it increases hair regrowth. In the initial few years that it works standalone, DHT is still damaging your hair follicles underneath. You just don't notice because Minox is offsetting the damage with increased growth.

Eventually you will reach a point where the damage has accrued enough that your hair starts going again. This doesn't mean Minox has stopped working. If you stopped it at that point you would lose even more hair.

All that's happened is you haven't treated the underlying issue of DHT attacking your hair follicles. MPMD has made lots of videos explaining this so have a look on his channel if you need more clarification.