Reassuring bronze and silver: it's still the same in plat

https://matchhistory.oce.leagueoflegends.com/en/#match-details/OC1/212965483/200842675?tab=overview

Even in Platinum, giving your team a 10k gold lead, all 4 first drakes as soon as they spawn, the rift herald, baron nashor, an inhibitor, being 8/0/6 .... Does not mean that your team won't throw the lead by getting caught repeatedly because "we're so ahead so let's have fun" and eventually throw the game. You're not alone in your misery, Bronzes and Silvers.