Let's say you are at a full ring table with the same players in the CO, B, SB, and BB and it folds to the CO. Then all the same action takes place. You don't think these are identical scenarios?
Perhaps it's worth repeating that this exact situation is a bad example of how hand ranges change in a shorthanded game.
Think of this way: a limper went up against 2 random hands and by showdown the 3 active players had the nuts, second nuts and sixth nuts respectively. That just doesn't happen very often regardless how how many players were seated at the beginning of the hand.
The easiest way to illustrate the concept is to think of how frequently KK runs into AA preflop, a very relatable example. At FR, if you're dealt KK there's a 4.32% chance one of your opponent will have aces. Against 3 opponents, that number drops to 1.44% (
source).
So in a short handed game, KK goes way up in value preflop because of the reduced likelihood of running into a stronger hand.
The same concept can be applied to all starting hands, but KJo is a great example to use since KJo is the quintessential 'top pair' type of hand. At full ring, flopping top pair while holding KJo is strong yet problematic because of the increased likelihood of a stronger hand being in the field, and as such should be played with an increased level of caution. However in a shorthanded game, top pair/decent kicker is much less vulnerable to running into a cooler and can/should be played more aggressively to extract value.
But if you insist on using this exact hand as an example, let's change the board texture.
Say the board runs out



.
Wouldn't you advocate the CO bet all 3 streets for value while holding KJo? But at full ring, that same runout might slow down a player holding KJo because of the increased likelihood of running into a stronger hand.