Yes, I agree with the author, people went to the rally because of the financial situation.
You ask why such a protest did not happen in the spring, but in January – I believe that in this case the mood of the people was well fueled by the video about the Palace, so you can see that people are shouting Putin is a thief and are carrying toilet brushes.
People shout “freedom to Navalny” – this is not a condemnation of the arrest, it’s an expression of support for his anti-corruption activities.
The government and economy: a couple of days ago, Putin spoke at a forum in Davos and he has a very clear idea of what’s going on and what should be done. While Navalny has no plan, no program, I don’t see how he could deal with the economy.
Navalny’s supporters want to give him more power, but I cannot see how it’s good idea. Navalny divides people into friend / foe and promotes violence, this is not suitable for a multi-ethnic, multi-religious Russia. Navalny knows how to spy and expose illegal schemes, he would be excellent intelligence agent, or anti-corruption investigator, or debt collector. Nothing of the scale of a city manager or president.