-shrugs- Not much of a conversation to have here. I don't find it impossible to recover from 1 death, I also frequently observe others do it. I don't have any way to reconcile with you on the topic. Your claim demands I ignore reality simply because your saying its so. If your behavior is to give up after 1 death your exactly the kind of player I am calling out with this thread.
Learning how to play from behind was one of the skills I had to learn. Losing lane with grace, don't bleed out gold, Bide for a power spike, know your counters and know matchups. This is a form of skill expression. If you can only win lane because you snowball vs some one who cant recover, your a weaker player. If you only win because every teammate does better, your a weaker player because your impacts not standing out.
Getting stuck is frustrating, when some one as good as you is ahead its hard. You should aim to improve and learn from those games. Figure out how to get back into the match. Roll over and force a loss for your team just makes you a shit teammate.
I am not in your games, I have no data on your playstyle or if you still strive for a win. I don't know if your able to lose lane with grace or what your knowledge is. The results should be clear in your history imo and if your struggling in your MMR then you likely belong there.
End of the day, If you want to quit after 1 death don't fucking play league, your mentality is just weak ,your ambition to win is lacking ,and your awareness of the game is terrible.