[Sauron the White]

They would not need to know this for a fact - conventional wisdom to which even Bilbo had access would give them reason to suspect it:

With all due respect, are you serious? "Convention wisdom" told the town that Smaug had a bare patch in his jewel encrusted armor? And you know this how? Nobody in that town knew anything until the thrush told Bard. Or maybe you know something that JRRT did not tell us in the text. Or you are basing this on the "convention wisdom" that any old dragon can be shot down if you hit it in the belly with an arrow. And the people of the town would know that how? Literature? Experience? Years of hunting dragons?

What is your explanation for how Smaug was foiled, if it wasn't by the destruction of the bridges?

I gave that to you in the post above. Again...

What was he "foiled" in? In destroying the bridge himself? Some of his fun was spoiled? Or maybe Smaug intended to wipe out scores of fleeing townspeople easily as they bunched up closely running across that bridge to possible freedom from his destruction? Again, his fun and intentions were foiled and spoiled. Or in landing upon it and walking over... for what conceivable purpose?

Nobody - your or davem - quoted anything to show that Smaug had a fear - to use the word several have used - of water. JRRT explains how it would hinder Smaugs fun - but that is clearly not the same as some phobia which would ground him. JRRT clearly says he intended to hunt down the townies in their boats upon the very water that he was supposed to fear according to some here.

And by the way, are we suppose to believe that while there were no places large enough for Smaug to land in Laketown, there was plenty of open space for him to maneuver among the various streets and lanes of the town with some elbow room to spare? Either its one way or the other here on the layout of Laketown.

It's true that the reasons behind this remain open to speculation, but Smaug's preferred attack is clear.

Clear as mud. There is nothing to indicate that Smaug intended to land anywhere in Laketown, let alone on the bridge or the same bridge was the one and only place he could have landed. No support for that at all. There is nothing CLEAR about that.

We have a dragon who was apparently foiled in his preferred attack because of the lack of a bridge - implying his preference was to attack from land, and he could not do so without the bridge - ergo, he couldn't land in Laketown. I would say an appeal to the text of this sort comes closer to "proof" (while it is not proof, and I doubt either side will arrive at any such thing) than speculation about dock space as a dragon-landing-strip does."

You are reading things into the text that are not there. Smaug flew towards the bridge and the author never mentions he wanted to land there for any reason let alone the one you place on him. Once again, we are supposed to believe the fallacy that the only place that would accomodate his landing was the bridge but then accept the idea that the streets were wide enough and there were enough open spaces for Smaug to freely go through the city and do his business. Which design of Laketown are you subscribing to because a belief in both those contradict themselves? And how much space is needed for a dragon landing strip? Is there something in the text that tells us that a dragon comes in like a 747 and needs thousands of feet of open space?

And I am still waiting to find out how the townspeople destroyed that bridge in such "little time" as was available to them.

tis is your explaination

This has already been addressed several times - the bridge was designed to be quickly destroyed. If they had designed it accordingly, a few cuts should have done the trick, and if it was their emergency plan, they likely had the necessary tools readily availiable and people assigned to the task.

You certainly have a great deal of faith when things are not there to support them. People without power tools, people without explosives, people who do not have any special skill in these areas are suppose to quickly rush out and destroy a bridge with ... how did you put it? ..... "a few cuts".
You have a great deal more faith than I do before this altar.