I don't even agree in 'hindsight' this situation was obvious. It's a hugely risky and crazy manoeuvre by Putin that may very well be his undoing.
The Russian economy is starting to crack, vast elements of key industrial sectors are collapsing.
There are no good cars being made in Russia, and even their garbage Lada's, which nobody wants, might not get made due to sanctions.
Car sales have dropped 80%, there's a vicious black market for spare parts.
Most Russians drive foreign cars. What happens when the all need parts?
Russian airline fleets cannot get maintenance or parts. They are being grounded.
Nothing about this invasion is obvious or doctrinal.
Entirely a surprise? Maybe not - but certainly not expected by anyone, even those paying attention.