Fallacy? But we can get from point A to point B.
So, we have an observation 'cover the infinite infinitesimal gaps from A to B', and we have a mathematical solution for it (calculus).
What exactly is the problem here? Sounds like you're tilting at windmills.
Observation/description hardly counts as adequate explanation(even if it's utilized into a rigged mathematical framework). Fact of the matter is, motion is assumed(and observed as you say), not understood or explained.
To the OP - it's unreasonable to ask a philosophical question and expect to get anything but philosophical feedback.