I disagree heavily it is blind luck. You're at your rating because you deserve to be ranked there. Everyone around you is similarly skilled (or lack thereof) and it is just your own personal ego thinking you're better than all these rando idiots. But it turns out you are also one of these rando idiots. There are some good write ups and videos out there as well dispelling the myth of "But I got gold medals, I carried!" mentality of low ELO players. The real problem is the game doesn't present you enough information to know what exactly is going on. But simply getting golds and still losing means you probably were doing something wrong.
I think you're taking blind luck into an entirely too deep of a context, or maybe i'm giving them too much credit. I think when people refer it as blind luck, even at my rating which is probably higher than most on this forums, you can't prevent yourself from dealing with a shitlord or two. Sure, its one person, ultimately you could carry a game against the odds and still win with that, but there are still situations where even if that potato sack did one or two things in a game of ult timers/combos can make a world of a difference. It's also pretty luck based if you get 5 other players who can perform versus 1 or 2 competent enough. I know that doesn't say much about the player themselves, but there are these situations.
Example, I had a game yesterday on Eich attack. Mind you, this is in a game w/ Masters and Top500's, where I would climb the wall on attack, pick BOTH healers literally. We would still get dismantled because the rein walked infront to where he gets walled off, then they aggress on our team and dismantle. Rinse and repeat on picks, no capitalizing. I mean, its not entirely my teams fault, but at the same time what more can I do when i'm dealing the damage, and getting the picks. Everyone is mentioning that we need to move as a unit, but our rein refuses to be in team chat. Is it a dipolmatic issue in which we have to convince this player to communicate and try to work this out? or why am I wasting my time telling someone something so basic, and praying that 4 other people can move according to this player?
There is a degree of luck in who you get matched with in terms of 5 different probabilities whether you get 3 support mains, or everyone is a dps god.
I had another game, in which was luck, again, towards a victory though. We made a piss poor defense on dorado, with like 5 minutes left on the clock for the attacking team. Guy choose Pharah at the last point, against a McCree who has been consistently doing most of the pickings and damage on their team, while the Ana on ours is desperately asking him to go reaper. He insists Pharah is the answer, does abysmal, ect. Arguments ensue, that duo queue leaves comms. His duo partner seemed to be the able to calm him? not upset? idk, he was basically saying not to blame him. The Ana wasn't a dick, more emotional that we needed a reaper but wasn't telling him he was ass, just his pick wasn't doing anything. I'm roadhog on this defense(i don't play many tanks) but by the end i'm silver at 4.4k, and was gold, so it couldn't have been higher than 5.5k. It's fairly obvious dps is a problem. I quick lock dps, and the game changes completely. Not trying to toot myself here, but gold ended at 24k and we won by shutting them down for 5 minutes outside the choke on point 1. I also think I tilted them because at a certain point during that 5 minutes, they eventually had 3 dps.
I easily know I could be higher, but I pref to play w/ friends and support them to be better.