I don't think it is likely this will happen, but I do think the possibility of war is being floated as a mechanism of fear.
"I don't know how WW3 will be fought, but WW4 will be with sticks and stones"
How often have we heard this-the implication being WW3 would be catastrophic, to be avoided at all costs.
And likely to make the sacrifice of Ukrainian territory more palatable to the masses to prevent the unthinkable.
I honestly think the next 4 years will see Ukraine forced to give up territory to placate Russia.
The time to worry IMO is if China mobilise.