No, I think you misunderstood. I'm not saying that the ostensible math isn't important to people ("I get +5, and you schlubs only get +2") but that if the system secretly only gave you a +2 bonus you probably wouldn't notice it for most skills.
That's only a 15% difference on a d20, You're correct, that's small enough that it would take a good while to notice. I was referring to "You have a +12, I have a +32 (or an even larger difference). I autosucceed on checks you need to roll a 20 for, and have a whole class of tasks I can attempt which you cannot." People will notice if they are being made to roll for things which they should autosucceed at, or being told they have no chance of success at things they should have a decent chance of success at. 15% either way, people might not notice. 60%+ relative difference (having +12 or more than another player and yet the game isn't applying the bonus) - people will notice that quickly.
When I'm playing 3.x as a player, for instance, for the skills I have large bonuses on, I print out a list of benchmark skill tasks for those skills I can take 10 on, take 20 on, or succeed on a 1 in-combat. I would notice immediately if I were made to roll for something that I should autosucceed at, that I should be able to "Just Do" without any dice rolled.
Take 1: Just do it in combat without rolling.
Take 10: Just do it outside combat without rolling.
Take 20: Just do it outside combat when you have at least a minute undisturbed to try repeatedly. Special note if they take longer than a minute.
They behave like a list of "Spells" you unlock by having your skills at certain levels of proficiency. Work dependably and with certainty. They also provide benchmarks to compare against for tasks outside of the benchmarks. "Is it easier than these things? If yes, then I don't need to roll under these circumstances, I can just do them". (They're like spells in that they are predictable an you can plan around knowing that you can do them and under what circumstances).
I might also note down the first benchmark task in those skills I cannot do even with a 20, and a few in my rolled range, so I have a sense of what is entirely beyond my abilities. It works out to about half a page per skill section, with maybe 3-4 pages total. Similar to having a couple pages of spell notes.
My point was that it's the belief in being superior at something that is rewarding, and that belief in turn distorts our perceptions.
That might be the case for small differences. But when it's a difference that results in fundamentally different capabilities, "I can balance on a leaf on a branch without rolling because my qinggong skill is so high, while yours is so low that the branch always breaks and you cannot even roll qinggong to prevent that" is more than a belief in relative superiority. My unfun from 5e math was that nobody gets actually good at anything relative to the RNG until you hit the absolute upper limits of ~+17 at level 17+, when that's around the level of "expertise" I want relative to the randomiser for the 'specialist', at level 1.
P.S. Here's the visualization from our Game of War simulation. X axis is how many turns the game lasted, Y-axis is card bias in initial conditions, size of the circle is how many turns were "war" (when the cards are tied). Mouse over a circle to popup the stats for that game.
View attachment 433039
The mouse-overings don't seem to work.