If you think that the time lost by remake for the other 9 players is "no harm done", then the LPQ you are experiencing is also "no harm done".
LPQ lasts for 5 games. 5 x 20 minutes is 100 minutes.
There are 9 other players in the match. 100/9 is 11.11111 minutes, or 11 minutes 6 seconds.
If you wasted less than 11 minutes 6 seconds of time for each other person, then your punishment is longer than the time you wasted. If you wasted more than 11 minutes 6 second, then your punishment is shorter than the time you wasted.
First is que time. That lasts generally between 1 and 10 minutes. For this exercise, let's say it lasted 3 minutes on average across the 9 other players.
8 m 6 s remaining.
.25 minutes/15 seconds for declaring a champion.
7 m 51 s remaining
4 minutes for banning, picking, and setting runes/summoners
3m 51 s remaining
Loading into game takes between 1 and 5 minutes. When someone DCs, it normally takes quite a long time. Let's be generous (to you) and say 4 minutes.
Now the 3 minutes it takes to remake.
-3m 9s
3 minutes 9 seconds x 9 is 28 minutes 21 seconds.
You wasted nearly a half hour more time than you are being "punished". The time you wasted was also the time of completely innocent people, and your time loss is a direct result of your actions.