I dont think you can make this argument after 3 years.Progress of advancement of Russian army might have been hampered
by resistance of Ukraine's raw troops. Ongoing cease-fire talk could also
be a factor. NATO-Europe also has been bluffing about deployment of troops
into Ukraine. The war looks to be more protracted than anticipated. It is
reasonable for Putin not to press forward in a rush.
If the war drags on and if military and economic aid from NATO-Europe
continue flowing into Ukraine the fall of Kyiv could be delayed by months.
That doesn't mean Russia is unable to beat Ukraine.
It certainly hasn't been for a lack of trying on the part of Russia.