It's not the dagger example, I comprehend that fine... I have no question about small static bonuses having diminishing value. I was referring to the original post, and even further back to the old threads about "Linear Fighters & Quadratic Wizards"... the numbers for the quantification of their power are as far as I can tell 100% arbitrary.
I provided the math for damage since that's the only actual quantifiable value... well the only quantifiable value that isn't expressly linear across all classes that is (HP & Saves are expressly linear)... a truly accurate graph of power would take all aspects of a class, graph their values per level individually, then graph an average of all aspects for each level and that average would be the accurate level of power for said class... however there are a myriad of non-quantifiable aspects of each class, and numerous other aspects that are difficult to quantify accurately.
Looking at what actually can be quantified both classes, within the confines of the class itself, are in fact fairly close to each other in power. The greater number of attacks per round for Fighters actually works to keep their output on par with the nuking abilities of Wizards. I'm not saying that Wizards aren't arguably more powerful, just that the power gap that is believed to exist is no where near as extreme as it's made out to be. That power gap is a gross exaggeration... I'm also saying that Fighters can actually out perform Wizards in a chosen task within the confines of the class. The main aspect for Wizards that does say that they are indeed higher power than Fighters is the simple fact that they can spread out their capabilities and become extremely versatile with little to no sacrifices, whereas a Fighter must choose to specialize in one field or another or be considered sub-par on all of them.
The damage aspect is likely why I have seen numerous times people push for wizards to take a battle field control perspective since the damage of mundanes is actually on par and can eventually even surpass their own. However, one can make the arguement that a Fighter can actually be more suited to battle field control than a wizard even. When it comes to grapples fighters have an upper hand in initiating grapples, while wizards have an upper hand in the ability to grapple multiple targets... however the wizards ability to grapple multiple targets plateaus and even dies off completely around mid game when their ability to initiate grapples stagnates and reaches a point where it's simply not possible to fail the opposed grapple check. Then there's anything with a saving throw, following class progression alone you lose the ability to reliably use much of anything with a saving throw around lv5 and then almost completely around lv15, that's a giant chunk of wizard spells that are virtually unusable mid to late game... and all of this is before you even factor in optimization for both sides... which BTW the defending end has far more and far better optimization options.
Even with versatility options at the wizards disposal, the action economy quickly reigns them back in. You may be able to play several different roles very effectively, but at any given moment you can only employ a single one of those roles. Sure you may have some options to improve your action economy but that would only really at best double your capability by letting you perform the same role twice or split your effort between two roles. Which I won't argue isn't a potentially huge boost in power, but those options have costs as well. Sure you can overcome those costs, but doing so requires stepping outside of the confines of the class itself.
If we are measuring the power growth of the class then everything must be within the confines of said class. Feats for measuring must be pulled from the bonus feat lists of both classes, feats from general levels and otherwise are ignored, items are ignored unless provided by a feature of the class (such as wizards crafting scrolls, wands, potions etc...), but you have to be reasonable with wizards crafting magic items as well... use the wealth by level chart to determine how much one could spend on crafting at any given level... and probably cut that value in half since they are reasonably likely to buy items as well as craft them... plus within the confines of the class you won't actually be reducing the crafting costs any...
I just feel that there is so much data that is completely ignored and even more that is utterly misconstrued via outside optimization that no one has yet to provide an accurate representation of the power levels for each class... sure you can raise the power level of some classes by a greater degree than others, but in a direct comparison is the disparity between the classes really truly as large as it's commonly believed to be? I honestly don't believe it to be, and from everything I can find they truly are very close in power.
FYI: the reason I dismiss outside optimization is because for every option you've got outside of the wizard class itself to optimize wizards, you've got an equally potent option that can be applied to a fighter. Outside optimization can eventually even blur the lines between classes. A fighter could for example, get access to a small assortment of spells to boost their melee prowess with the right selection of feats, prCs, and other classes. Even magic items provide equal benefit to a fighter as they do a wizard, the difference being that a wizard may come to rely on magic items more often due to having a limited resource for their spells. Outside optimization just muddies the results and can be used to create bias, whether intentional or not. One might believe that a wizard has a greater range of optimization than a fighter, but that doesn't make it true, a fighter can be optimized to be just as powerful as the most optimized wizard if one knows what they are doing. The fact that many believe wizards to be unmatched in optimization and fighters to have little to no optimization options just furthers my point, outside optimization invalidates comparisons of class power due to bias.