Time will tell.
But it’s not an unrealistic speculation. In 2014 the Scots voted 55:45 to remain in the UK, but at that time the UK was part of the EU and one of the arguments against independence was that independence would cut Scotland off from both the UK and the EU. Brexit has changed all that; now, if you want to be in the EU, you have to vote to leave the UK, and those who were motivated by this argument to vote to remain in 2014 will now be motivated to vote to leave.
But there’s more. After the Brexit referendum, the British government decided to pursue a “hard”
Brexit - minimal connection to the EU - and has successively hewed to harder and harder forms of Brexit. They are not compelled to do this by the refernedum result; the referendum result is satisfied by any model of Brexit. And, while all forms of Brexit are injurious to Scotland, the harder the Brexit, the more damaging to Scotland. So the British goverment, at least arguably committed to Brexit by the referendum result, has voluntarily gone further and embraced a form of Brexit which does unnecessary harm to Scotland, ignoring both Scottish interests and Scottish wishes.
And what this underlines is that the British government is not at all sensive to Scottish viewas, concerns or interests. The UK union is badly unbalanced in favour of England, and the Scots are getting a graphic illustration of how this plays out when it matters. This will hardly endear them to the union.
There is one consideration which goes the other way. In 2014, an independent Scotland would have been part of the EU along with rump-UK, and this would mean a high degree of economic and regulatory integration, which would tend to minimse the economic impact of independence. If the UK leaves the EU without a deal and trade on WTO terms and independent Scotland joins the EU, there will be a much more signficant economic border between the two countries than would have been the case in 2014. That will tend to increase the economic costs of independence.
Tl;dr: The way in which the UK government has pursued Brexit has greatly strengthened the political case for independence, while also increasing the economic cost of independence. How will all this net out? Hard to say. But the two possible outcomes are (a) an independent Scotland, or (b) a disgruntled Scotland, financially tied to a union in which it is gratuitously injured, increasingly disregarded and increasingly unhappy. A happily United Kingdom is not a likely outcome here.