Ulhumbrus: <Atterdag>
I can think of one argument to support the taking of risks: if Caruana was likely to lose the match unless he steered for uncertain positions what had he to lose?
On the other hand I am not sure that Caruana's strategy failed him in the match that he lost: It may have gained him the best result that he could gain. Carlsen was too strong for unreasonable risks to work. Boldness was necessary but if Caruana did exercise it without straying into undue boldness perhaps that was the best result he could expect.
If Carlsen was the higher rated player we can assume that the chances would favour him if both players chose the best strategy they could, but could they both in fact do so? If the best strategy for Caruana was to accept uncertainty with equal chances and the best strategy for Carlsen was to avoid uncertainty I am not sure that if Caruana were to choose uncertainty Carlsen would be able to avoid it. In fact if he were to try it he might lose.
Now suppose that both Caruana and Carlsen were to deliberately choose difficult positions where neither player could avoid mistakes would the chances still favour Carlsen? I don't know.
If Caruana had a choice between probable loss and uncertainly where his chances were not worse he would have nothing to lose then by choosing uncertainty.
One argument for this is one that applies to the match Carlsen - Anand World Championship Match (2014)
It was suggested indirectly by Kasparov.
Carlsen is strong in the ending, strong positionally, strong when choosing to attack, a very strong all round player, like a younger version of Kramnik, in fact.
This suggests regarding Carlsen as a younger version of Kramnik.
Against Kramnik Kasparov said that Anand had chosen the right way, to <kick sand in his opponent's face> by playing enterprisingly in Bonn.
This suggests that one way for Anand to win against Carlsen was to regard Carlsen as a younger version of Kramnik by playing less conservatively in the first few games at Chennai in 2013.
So we may think it possible that Caruana would have nothing to lose by accepting uncertainty with equal chances if the alternative were a likelihood of defeat.
Possible, meaning that I don't know. To return to what I said earlier, it is up to Caruana to make that judgment.