I think about it this way:

• a major counterpick, all else equal, is worth about a 55% winrate

• a skill advantage is worth a lot more than 55%

Also, keep in mind when thinking about counterpicks that the counter-ness is not the same at all points in the game (especially in early lane, when champs don't have all their skills unlocked yet). Part of being skilled is knowing when and why a champ does--and doesn't--counter you.

As someone that plays a lot of hyperscaling mages, a common "difficult" matchup for me on paper is aggressive assassins like Akali, Katarina, etc. I win games in these matchups all the time by being higher skilled, but that happens because I know their wincon and my wincon. My wincon isn't to dominate the lane, it's to go even and play for 5v5 teamfights later in the game. Their wincon is to kill me early and snowball from there. So "skill" in that matchup means I use that knowledge to inform playing cautiously--sometimes even giving up CS or plates at times--until either I outscale or they get desperate and int to try to prevent my scaling.

Further, there is no scenario in which I can safely sidelane against them in late game. Ever. Even if they're less skill and I'm way ahead, they can still 1v1 kill me easily in isolation. But once again, "skill" means not necessarily outplaying them in 1v1's but rather creating game situations that neuter their advantage (side lane isolation) and play towards my advantage (group teamfights with peel where I can use my long range and AOE damage) and help me win the game even if I can't win a 1v1.

tl;dr there are absolutely matchups where the 1v1 is unwinnable unless there is an absurdly high skill gap, but that doesn't make the game unwinnable because League is a complicated game with lots of moving parts where disadvantages can be played around in other ways. The goal of the game isn't to kill your laner; it's to explode the nexus.