"I fail to see the logic of this position. What is it about a no vote that guarantees either of these things?"
The point is that individuals will make a Yes/No/abstain decision on what they believe will happen - and how it will affect them.
This may be unwise/misguided or turn out to be sound (won't know for several years, and even then so many things will have happened - not just in the UK - that it won't even be possible to say it was ' because Scotland voted Yes/No').
There are people who 'want all the answers before they can decide'. But that is just as unrealistic as believing that everything in the "white paper" will come to pass.
Not enough people seem to realise that this is (just) the thoughtful 'vision' of the current (SNP) government.
IF there is a Yes vote, there will be a newly elected government in Scotland to 'deliver' independence - this will not necessarily be an SNP majority one.
Before the referendum there is a Euro election. That will change (some) things. It seems likely that UKIP will win a few more seats in England and probably none in Scotland.
That will reinforce the notion that 'Scotland is different' for some people and may increase the number of people thinking of voting Yes. It may also push the UK Tory party to wanting to pull out of Europe (even more than they currently do).
IF there is a Yes vote it may be that most countries will be keen to keep/have Scotland in the EU in the face of a stronger possibility that rUK will vote to leave.
Of course that depends on there being a Tory government after next year's election. At the moment that seems unlikely. A Tory/LD coalition seems unlikely too.
(Most?) Labour politicians want a No vote. This is for perfectly understandable unionist (non trade union perhaps!) reasons
They fear a future where rUK could never have a Labour majority at Westminster. That of course (as at present) depends entirely on whether the party appeals to enough voters in marginal seats. There is no particularly good reason why Labour should want/need/ be able to rely on 'safe' Labour seats in Scotland.
If there is a No vote, no doubt some parts of the SNP will go into shocked depression, but I predict that it will energise Salmond & Co to ensure that the election returns as many MPs as possible to Westminster to hold the balance of power there and speed up the negotiations for DevoSupaMaxPlus - which may be what he wanted all along.
Labour might also take an interest in proportional representation for future UK elections - I'm sure the LibDems and SNP would help with that!
It'll certainly make those who stopped there being a third option on the September ballot paper look foolish.
The future is unwritten.