More on your "legendary player" math:
Let's imagine the rating of "below average" to "legendary" players to lie on a spectrum, with "below average" career players on the far left, "average" players in the middle and "legendary" players on the far right:
l-----------------------------------------------------l------------------------------------------------l
Okay? That's our "Spectrum of Player Worth". And while technically any player residing to the left of "Average" could be considered "below average", let's assume that there is a range of acceptable performance for each moniker rather than a set above-or-below point. Now, let's take the respective aspects of Fox's game--offense and defense--and put them on the spectrum (his offense, as already pointed out multiple times, is decidedly average and will lie directly above the "average" point, and his defense, decidedly "legendary" will lie directly above the "legendary" point on the spectrum).
And for now, let's assume that a player's worth is equal parts individual offense and defense. That would make Fox's "Total Worth" lie exactly half-way between his offensive and defensive points on the spectrum
l-----------------------------------------------------l-------------------------l----------------------l
Looking at this, Fox is assuredly more than just an "average" MLB player, however his total worth isn't exactly close to what could conceivably be considered legendary, and that's assuming that total worth is equal parts individual offense and defense.
Realistically, Fox's total worth lies farther away from "legendary" than previously shown because while team defense might be closer in relative worth to team offense, it would be a bit naive to think that individual defense is on-par (in terms of the effects each individual phase has on winning] with individual offense.
Again, there is no doubt that Fox was a very good player, but to say that his superb defensive skills rescued his very average offensive skills and propelled him to "legendary" status as an overall player is, at best, overly simplistic.