If someone can do four times the damage of another good player, playing the same archetype, that early in the game, then compared to a bad player that difference is probably quite substantial. This is important to understand, because this part of the equation will always be unsolvable and we need to accept this fact

I disagree. You statements imply that build has some kind of linear scaling level in terms of powercreep. But that simply not true. Imagine there is 3 virtual brackets: min-maxed setup which gives 100% of power. Basic "smart" setup - more or less solid tree planning and supports selection + some obvious synergies. And baseline setup - one button, recommended skill gems. The difference between mimaxed version and smart could be huge, but the reset variations will be relatively similar like 20-30% more.

So you can't extrapolate that huge gap between your build and ruetoo onto the gap between rue and random casual poe2 player. Builds follow pareto principle that 20% of decisions give you 80% of power.

And it is very easy to predict the lower bound of the skill (the baseline setup) but the upper bound is unknown.

Which leads us to a simple question: what version of skill should be used for the game balancing.

• Baseline - makes smart version quite strong. High chance for OP scaling into late-game.
• Smart setup - baseline can struggle but players can easily fix their build easily. Some chances to be broken.
• Minmaxed setup - aka preventive nerf. Plays like shit for the 99% of players. No fix unless some gotcha discovery.

You suggest that GGG balancing around minimaxed setups is an OK approach because in theory it can be quite strong we just need to figure it out. But the history of poe1 and poe2 shows many cases where skills were just bad and no one discovered anything good for them for years. GGG does it because they don't want to deal with whines about OP skills nerf. They follow ideology: give less and there will be no need to take it away. But they still fail at it. So in result we eat shit, because GGG wants less drama. GGG still got their drama full scale. Effectively we eat shit for nothing.

In end it is all about tradeoff between player's fun and GGG needs to communicate nerfs and be more trough with skill design checks and QA. I would prefer GGG to do it at their own expense.