That's because right now, all the new accounts are rushing to get into the mix, don't understand how placements work, and many accounts are literally ranking their new accounts right now, thinking the rank they have right now is going to stick.
At the same time, some other players just don't care, because they are are aware it's still preseason, and know that their next season rank won't change much from now, so if they feel a game is going south at queue, or shortly after, they just throw. Like Season End, it's the perfect storm for negative records unless you have a reliable duo you can fight out with and tilt the so called tilted odds.
op.gg to screen your teams, and I'll bet you right now 4/5 of your games will have either someone who is unranked, or someone who is just ranked, but plummeting in scores like 33% wins because they were placed wrong.
The best time to play is mid season, because there are much fewer account starts, and people are actually trying to climb.
For the record: this account is in the wrong elo, and I drag games out 40 minutes, because even in this toxic environment, I usually can stall a game an extra 15-20 minutes until my team who was horrible either wins, or we lose a closer game. Just depends on how much my champ can carry, since I main support (Zyra can hard stall a game and carry, Nami can soft stall and carry, Sona can hard stall but soft carry, Morgana can soft stall and soft carry, Karma can hard stall, but soft carry (eventually gets pushed in).