Try to imagine if say US miltary is in war against Ukraine. There wouldn't be moving convoys, because all would be destroyed and US forces would be in Russian border by the end of first month. End of story.
That's the way such things are done. Not this.
The United States’ shock and awe doctrine which includes the indiscriminate bombing of civilian targets is a campaign of terror and mass destruction. Yes it leads to the quick capitulation of a hostile state and their inability to mobilize further fighting age men, but what do you think happens to the latter after the peace deal is signed?
They all turn into insurgents and blend into the civilian population.
Unless you are willing to mobilize hundreds of thousands of soldiers to occupy, garrison, and police the humanitarian disaster you have just created, you’re going to have an endless quagmire on your hands.
Which is exactly what happened to America in Vietnam, Iraq, and Afghanistan.
The Russians to their credit understand the long term consequences of unleashing unrestricted destruction on a civilian population they intend to win over to their side, and have chosen a long and careful war with justification for every escalation of violence in order to undermine the credibility and popularity of the Zelensky regime.
For military planners focused on a rapid victory at all costs, this seems like the unwanted involvement of politics into the battlefield hampering generals.
Yet the last thing Russia wants is to fight a decades long insurgency trying to garrison hostile territory and a population which hates them. Let’s see who gets overthrown first: Putin or Zelensky.