Considering only foreign ones (local ones are already covered), the first explanation I can find is that for most of them it would just be an expensive and pointless exercise.

The time and costs involved to setup, maintain and enforce such a system would be ridiculously high compared to what it would bring in.

Another answer (still only considering foreign businesses) would be that for companies making so little, the burden could be much greater, hindering their growth (and future taxability).

And that's just from the tip of my head