This article is a very good analysis in general although this particular conclusion seems to be an overstatement in my opinion. Most people I know in Russia can see a causal connection between Putin's politics and the economic situation.
This is indeed a very valid point in general. I just don't think it specifically applies to modern Russia for two reasons:
1) especially the older generation in Eastern Europe has a strong tendency to blame everyone else ("them") for any failures; the attitude is sometimes called Homo sovieticus (after Mikhail Heller's book) or "sovok" in Russian
2) the whole point of Putin's "raising Russia from its knees" movement was about the state taking more responsibility
100% agreed, we see these protests with non-economic trigger all the time. We saw that in Ukraine, USA, Russia, Poland, Middle East, Hong Kong etc.
And yet, when I think in particular at this other part:
> "Stolen elections, politicians who cheat people’s expectations, police brutality and the persecution of popular public figures can still shake people out of their lethargy – but economic injustice no longer can."
...of course, economy is always to some extent part of the issue, but it's rarely the core demand. It is not, for example, in the case of Belarus in recent months. But even back to Russia, what united the last big wave of protests in Russia (2011 presidential elections to Bolotnaya), the unifying issue was "for fair elections", not economy (even if Udaltsov and other leftists were part of the protest).
Tsikhanouskaya is not a threat because of its distinct economic policy. Neither is Navalny (even if that is already a different story).