The luck vs skill factor of ranked is not what people actually think it is. In this post I will explain, if your butt is sensitive please just stop reading now because it may get hurt.
Most people believe deserve a higher rank than they are. Some believe they deserve an extra couple of divisions while some believe they deserve an extra tier or two. When it comes to the ranked ladder the difference between certain ranks is a lot higher than others; the difference between plat 5 and plat 2 is much larger than the difference between silver 5 and silver 2. People expect a linear growth between rank and skill equivlancy and this is where walls get created which make people feel like they can not climb.
Now I am not going to say there is no luck at all in ranked, because that is obviously not the case. There will always be games where you will lose even if you are better than the 9 other people in the game. The fact is that if you are a full tier higher than your current rank the games will be so easy that even having those games every once in a while will not matter because you will be such a consistent advantage to your team that you will of course win more than you lose.
The real problem is when people get close to their skill level but not at it yet where the luck becomes more of a problem. If someone is Gold 5 skill it is possible that they will get stuck in Silver 2 or Silver 1 for a bit because even though they are better than Silver 1 or Silver 2 it is not by enough to make a big enough consistent advantage. If that player in silver 2 had gold 3 skill then they would easily climb to gold 5 and then start to feel the 'luck factor' while trying to go from gold 5 to gold 3.
I see people call Plat the ultimate elo hell a lot and after climbing it several times and quick climbing smurfs to that elo in order to use it to practice new champs I can see why this is the case. As I said earlier Plat 5 to Plat 2 is a much greater difference in skill than silver 5 to silver 2. So this means people that were climbing pretty consistently now hit a wall and do not realize how much better they actually have to get in order to climb.
When you start to feel the luck factor kicking in that simply means you are at your skill level or getting really close to it. In lower elo that could mean you are within a 3-4 divisions and as you get into higher elo it usually means you are within a division or 2 max. In order to break through to the next level by winning consistently at where you currently are you need to find ways to drastically improve your performance in your games. Doing the same thing over and over again as a P4 player in P5 will eventually get you into P4 but it might take you 50-100 games and that is because a P4 player is only slightly better than a P5 player. If you were a P2 player the P5 to P4 climb would feel ridiculously easy because of the skill difference between those ranks.
The next problem that demotivates people is their past season ranks. People need to realize that last season ended and things have changed. Being Diamond 5 in S6 does not have a lot of weight in S7. A lot of people climbed to D5 by either abusing Dynamic Q or using something that was broken during S6. It is possible that someone could have gotten to D5 last season by spamming a champion that was top tier with last seasons meta that now will be stuck in low plat this season because it is no longer strong. This is what seperates true diamonds from what I call diamond spikers; true diamonds will climb back because they have diamond fundamentals while diamond spikers will struggle somewhere between high gold and mid plat because they were only diamond from spamming something that was powerful at some point. So overall, doing what worked in S6 will more than likely not work in S7 and adaption needs to occur for climbing to happen.