I mean, from a horticultural perspective, there is some potential to gain more of other nutrients, in that if you have more energy, you can develop a larger root system, or generally more effectively, better feed mycorrhizal associations (fungal hyphae are much finer than root hairs, so can get into smaller cracks, and fungi can "acid mine" nutrients out of mineral grains -
I would think that, in general, it would be a square-cube ratio issue or a set of them combined with other limits. Surface area of root system versus mass of plant, for example. The constraints on the growth of the root system versus the constraints of the growth of the main body of the plant, for example. Or, to grow bigger (and be denser in Calories) the plant may need to suck up more water which, theoretically means more nutrients, but the soil is not some homogeneous reservoir of mineral water. Different nutrients will propagate through the soil and the moisture in the soil at different rates. So, change the rate of uptake and the nutrients will end up more dilute in general, but that will also happen at varying rates for different nutrients depending on factors like their solubility or mobility, rates at which other materials in the soil re-absorb them, rates of replacement from the surface weathering of rocky particles, etc. So, double the intake rate and the flow of some nutrients might nearly double, while the flow of others stays virtually unchanged. Aside from nutrient uptake, there's also nutrients produced in the plants. Once again a surface area issue. Many of those nutrients may be produced in parts of the plant that scale less relative to the mass of the plant. For example if nutrient X is produced in the leaves of the plant and the plant doubles in mass but only increases 30% in leaf surface area.
Aside from all of that, there's simple bio-regulatory processes to consider. Basically all organisms have an energy storage mechanism. Fat, other oil storage methods, carbohydrates, etc. If whatever method is used to store energy in the organism tends to have a lower proportion of other nutrients relative to Calories, then if the organism has extra energy to store, the ratio of extra nutrients to Calories of the entire organism will shift from nutrients to Calories.
So, like you said, definitely more theoretical potential to gather nutrients, but most scenarios seem to make the outcome of having fewer non-Caloric nutrients relative to calories more likely.