Oddly enough, a similar thread has been going through the medieval recreationist's board, and the best opinion I've seen there is that "the sword is the soul of the samurai" is meant to indicate that it is amongst the various tools used to perfect the soul. The various actions connected with the sword-- polishing, drawing, cutting up bandits-- are to act as means of meditation, which leads to greater self-awareness, and thus enlightenment. If a samurai were in a different line of business, he'd have a different tool (the rake is the soul of the gardner). Remember that they're not thinking of "soul" in a Christian sense, but rather a Shinto-influenced Buddhist sense, so unless you're a giantic stinkhead you're in little danger of going anywhere more hellish than into another human life once you die. The stuff you've got, swords, shoes and skin inclusive, are all jettisonable and of little account.
On a more practical front, given the rather stressful life of a working sword... well, there's a reason they carried a spare, eh? Sword breakage was a well-known hazard of the samurai life-style, and a smart fella kept an eye on the tell-tales of fatigue (why does my sword go "clonk" instead of "ding"?). Those who weren't aware of the state of their blade were more likely to have it break at the wrong moment, which could lead rather quickly to giving up of your current collection of stuff and starting a new life... in a highly literal Buddhist sense

A samurai with a broken sword and no money to replace it was cursed in a sense-- people pointing and laughing, even more trouble making money, spending WAY too much time worrying about how to get a new sword and neglecting meditation, and a pretty tough row to hoe as far as using seppuku to get out of the situation. It's not eternal damnation, but it would drag something fierce.
This is not to say that there weren't those that came at it from the other way, and assumed that the better the sword they had, the better a person they were-- I'm looking at that bullish chap in
Daisho. Much the same thing happens in Christians who get a little stirred around between whether to be impressed by the church (pile of bricks and lumber) or the idea that prompted building it. Tricky thing, this philosophy... way to hard for a simple
hanshi like me.
"...[H]uman beings are given free will in order to choose between insanity on the one hand and lunacy on the other..."
Aldous Huxley, 1946