Thank you for pointing this out.
From the viewpoint of mathematics infinity is not a number. It is a concept. Therefore technically we cannot put infinity into a mathematical calculation.
Mathematically as the number by which we divide the number one
becomes larger and larger the resulting number becomes smaller and smaller.
However the situation of falling down from the spiritual world is not subject to the mundane laws of mathematics. In this case there are spiritual principles at work.
We learn from the Brahma Samhita (5.32) that there are infinite material universes. Therefore there must be an infinite number of souls who have fallen from the spiritual world to inhabit these infinite universes.
What are the odds of an eternally liberated soul who is enjoying a life of bliss and knowledge in the spiritual world deciding to try to enjoy separately from Krishna here in this material world? A very, very, very small number.
But since there are infinite devotees in the spiritual world that small percentage ends up being an unlimited number of souls who fell into this material existence.
This is the point I was trying to make.
I hope this meets you in the best of health.
Your ever well-wisher,
Sankarshan Das Adhikari