When the "Better together" campaign was opened by Alistair Darling he made a statement in the first paragraph that "..of course Scotland could survive on its own..." or words to that effect (I am too lazy to look up the exact wording). By those who resist going along with the classical refrain, that Scotland is being subsidised by England, that Scots are hopelessly inept/incompetent, etc. it is self evident that Scotland could survive as well in independence as it now does within the Union. There is a fairly lengthy list of countries which suggests that Scotland should be able to do better than it does at present, assuming they are indeed not inept/incompetent, because so many countries of a similar population size, having similar resources and location do so much better than the UK. As things stand, by virtue of being in the Union Scotland will never do better than the UK - by virtue of the numbers England will always dominate and it follows that it might be argued that English ways are a drag on Scottish potential.
The unbecoming suggestion that independence for Scotland as a concept is the private reserve of Nicola Sturgeon is obvious nonsense. The 2014 referendum showed very clearly that not only was independence then an attractive prospect for nearly half of those who voted but also that the very real prospect just before the day that the result might be "Yes" terrified the establishment south of the border. An entire trainload of functionaries was commissioned and despatched forth to try and dissuade Scots by playing up horrors in prospect and extol the promises if only they would vote No. That was when (for the first time ?) the label of Project Fear was applied to these tactics.
There is some evidence that increasing numbers of Scots see less and less virtue in maintaining the Union and that in turn indicates a decreasing fear of doom if Scotland were simply to choose a situation where Westminster no longer matters. Many of these people will be aware of the sentiments offered south of the border, sentiments regularly/often quite clearly expressed on Answerbank.