Daf Yomi Nedarim 25a: Is Shishim Ribo A Guzma Or A Possibility

Based on the Mishna and gemara in Nedarim, it seems apparent that 600,000 passersby on a given street is an impossibility. The Mishna states:

Mishna:

נדרי הבאי
אמר קונם אם לא ראיתי בדרך הזה כעולי מצרים אם לא ראיתי נחש כקורת בית הבד

Vows of exaggeration:
If he said: Konam if I did not see on this road like those who left Egypt; If I did not see a snake like the beam of an olive press.

And in the gemara, they object that such a large thick snake is a possibility, such that Shmuel reinterprets it to be as smooth as an olive press. But there is no such protest about the person seeing as many as those who left Egypt on a road.

This has huge potential halachic ramifications, for many of the current laws of eruv are based on the presumption that our streets are not considered public domain but rather karmelis, such that one can use tzuras hapesach on it. And this from a diyuk that Tosafot makes on Shabbat 6b. The gemara:

The Master said: 'That is [absolute] public ground.' What does this exclude? — It excludes R. Judah's other [ruling]. For we learnt: R. Judah said: If the public thoroughfare interposes between them, it must be removed to the side; but the Sages maintain: It is unnecessary. And why is it called 'absolute?' — Because the first clause states 'absolute', the second does likewise. Now, let the desert too be enumerated, for it was taught: What is public ground? A high-road, a great open space, open alleys and the desert? — Said Abaye, There is no difficulty: The latter means when the Israelites dwelt in the desert; the former refers to our own days.

On this idea of the midbar being specifically when it was populated, when Israel was in the wilderness, Tosafot makes a deduction that in general for reshus harabbim, it is not a reshus harabbim unless 600,000, that is, those equal to the number (of men) who left Egypt, are present. They write:

Presumably, people discuss this, and offer resolutions, but I've never looked into it myself.