Why is the current math community not contributing to machine learning much?

This is a interesting question but, in my opinion, are several misguided or at least questionable conceptions:

1) The future is what matters.

Scientists should concentrate now on what will have most impact in the very long run. Why is that? I certainly do not agree.

2) The future is clear.

Even if you agree with predictions about the Future (like Brendan McKay's prediction which I tend to agree with) you should acknowledge that even a plausible prediction of this kind might be wrong, there are various plausible developments which may be competing, and the time scale is also very unclear and of great importance.

3) Long term projects are most fruitful

Even if you do give high weight to long term projects and it is clear to you, say, that computers will have vast impact on mathematics, it is not clear at all that your own efforts in such a direction will be more fruitful than effort in other directions. Long term risky projects more likely fail.

4) It is problematic if non-mathematicians will bring major (or even the major) contribution to future mathematics.

It is possible that current non-mathematicians will have major, even dominant, long term contributions to mathematics. What's wrong with that?

5) Mathematicians should mainly concern about ML's impact to mathematics

There are more important and more immediate applications of ML which are not to mathematics. This could be as tempting or even more tempting to mathematicians who want to get involve in ML. If you can see how your mathematical ideas could contribute through ML to autonomous driving, go for it! This can be more important than automatic theorem proving.

6) The "math community" allocates its manpower.

7) Impact of mathematics to a new area is measured by current mathematicians working on it.

It is probably the case that mathematics and the work of mathematicians in the past (along with statisticians, computer scientists, physicists, ...) had much influence on ML current development. A related thing is:

8) Impact of mathematics to a new area is measured by direct attempts of mathematicians aimed for this area.

And finally

9) Mathematicians do not contribute to current ML. I am not sure this is correct.

As a matter of fact, I recommend to look at the book Understanding Machine Learning: From Theory to Algorithms by Shai Shalev-Shwartz and Shai Ben-David to learn more.

Actually there are a lot of mathematicians working on Machine Learning technics but it is unlikely that you can access their work. In the U.S., the NSA "is actively seeking mathematicians to join a vibrant community of mathematicians, statisticians, computer scientists, and other intelligence professionals to work on some of our hardest signals intelligence and information security problems." They are many mathematicians employed by the NSA, you can apply there if you are interested. Here is an article describing some of the consequences of their researches in the field of machine learning. I guess this answers the firt part of your question: there are a lot of manpower dedicated to ML from a mathematical viewpoint (but not all mathematicians want to be part of it.)

You seem to believe that the completion of a human level A.I. is in reach. There is no evidence that this is the case, despite the billions grants national Science agencies are pouring over scientists. We have been there already. Here is a famous quote from Herbert Simon, Nobel Prize-winning AI researcher: "There are now in the world machines that think". This quote is from the sixties and probably got him to harvest a few millions in grants for his researches. This should not prevent you to think on your own, and take these kind of assertions with a grain of salt.

Finally, there are many efforts going on now when it comes to automated solvers. ML is one of them but mathematicians have since long learned not to put all their eggs in one basket.

Well, there is Mikhaïl Gromov who considers universal AIs and argues "that the essential mental processes in humans and higher animals can be represented by an abstract universal scheme and can be studied on the basis of few (relatively) simple principles".

Personally, I think that, machine learning together with mathematics is not enough to create an universal AI, we need a lot of neuroscience and physics.

Also, for some people, mathematics is not about results or long-run development, but more about personal understanding of things and theorems.

Anyway, there is a very related question:

Why is the ML community not spending enough manpower for developing mathematics, even though "Mathematics is the queen of sciences" ?