For you, probably not, but I have never heard of anyone else wanting a premade base that size. So if any company made one, their potential customer base might be just one, namely you, and that would not be enough demand to produce it economically. Although with engineering and tool up costs, they might be able to make one for about $50,000.
Once the engineering and production issues are taken care of, then they can be produced economically. But, those costs have to be spread across the total assumed production demand, which for a base that size is very small. If you notice, that, and one other, are about the only "square" ones that are not 34" or 36" deep.