Hi Johnny,
You said, “I have an impression that when something is quantized, it tends to have a fleeting nature.”
The part about “fleeting nature” is a misinterpretation. I see that all the time.
For example, a suddhāṭṭhaka (created by the javana power) can last billions of years, until destroyed at the end of a Maha Kappa (i.e., when the Solar system is destroyed.)
The main idea that the Buddha tried to teach was that anything “material” changes even momentarily (but that “momentary change” can be very small.) For example, our bodies undergo momentary changes, but we can see “significant changes” only over the years.
– Furthermore, things can change unexpectedly over time. That is the “viparinama nature.”
Of course, our thoughts (citta) change very rapidly. It is appropriate to say that thoughts have a “fleeting nature.”