I think this is true from an economic engineering perspective. If a patent doesn't require investment, it doesn't need a patent to ensure that investment can be

I think this is true from an economic engineering perspective. If a patent doesn't require investment, it doesn't need a patent to ensure that investment can be recovered. From an enforcement perspective it could get pretty ugly. Also, the law is at its best when it deals in definable concepts. Large is relative. For Google, an investment to large to be pursued on a whim has 4 or 5 more zeros than it does for me.