11 plant garden only suited for smaller plants?

[critter]

OK here's another stupid "11 plant" question. Why is the 11 plant garden only suited for smaller plants? How come I can't grow huge tomato plants in it when the larger 1 gallon system still uses the same size grow cup? Would I need a larger grow cup to grow a large plant? What difference does it make if the roots are only going to continue to grow through and outside the cup anyway? I want champion size critters, not a bunch of small ones.