If Shen gets sated and builds a BotRK
Let me stop you right there.
Average player income per-game is only ~11,000. Works out to about 3 major 3k items, 1k in boots, and 1k in the bank when someone's Nexus goes down.
What you build ultimately determines what class you are, your intended archetype determines how effective you are at doing it. Full AD adventures Thresh is for all intents and purposes an ADC. Full tank Teemo is a tank with a respectable global taunt. On-hit AA Shen is a squishy melee carry.
Squishy melee auto-attacker is a heavily flawed archetype to want to be for several reasons, and Shen doesn't really have the kit to pull it off. Realistically Yasou is pretty much it for being competitively viable with that stratagy, and that's even a little questionable in his current state.
You should pretty much never have 2 full-offense items like Devourer and Kingblade on Shen. 1 full offense item will already keep you notably squish from lanning phase until roughly the end of mid-game when team-fights start happening, where you'll only be 50% tanky. 2 full offense and you're likely only 33% tanky by the time the final, decisive team fight is statistically happening.
My point here is that planning on 2 glass-cannon items for a tank or fighter/tank is a recipe for disaster, planning on a build that uses both is not going to lead to optimal builds.