[2021] ...these beginner bots just layered their CC better than what I see in my Diamond games.

I'm not sure how it is now but the bots had very precise scripts way back when. E.g. Veigar bot would only walk towards you if he could combo you and he would with precise E W Q R. If he ran away he could not OTK you. EDIT: Banshee's Veil would confuse him and he'd try to OTK you and not succeed leading to free kills. This was very useful in the doom bots of doom to win at level 100. TL;DR the bots have scripts to layer CC and time things like...well robots.

That's the kind of scripts I'm talking about! It really goes to show the value in "knowing your lines" like when a better player kills you and lives with 10HP, it's not luck, it's that they knew they'd live.