I removed white sugar/corn syrup from my diet and my teeth have rarely had issues for many years. Even when I skipped regular teeth brushing in the past.
Take these anecdotes with a grain of salt.
Assuming you're not predisposed to other issues and that you still brush your teeth at least once a day most of the time, that's the speed of decay you should expect and the timelines you're working with. The daily, monthly or even yearly progression is miniscule, making it difficult to observe if it has been slowed or halted, especially in messy anecdotal tests.
The exception being tooth grinding, which can go faster and is easy to measure.