There are many dumb risks that can easily accomplish the same, wipe us out. It doesn't need superhuman intelligence to do that.

Yes, there are dumb risks that could wipe us out just as well: but only a superhuman intelligence with different desires than humanity is guaranteed to wipe us out.

I also do not see enough evidence for the premise that other superior forms of intelligence are very likely to exist.

You don't need qualitative differences: just take a human-level intelligence and add on enough hardware that it can run many times faster than the best of human thinkers, and hold far more things in its mind at once. If it came to a fight, the humanity of 2000 could easily muster the armies to crush the best troops of 1800 without trouble. That's just the result of 200 years of technological development and knowledge acquisition, and doesn't even require us to be more intelligent than the humans of 2000.

Further I argue that there is no hint of any intelligence out there reshaping its environment.

We may not have observed aliens reshaping their environment, but we can certainly observe humans reshaping their environment. This planet is full of artificial structures. We've blanketed the Earth with lights that can be seen anywhere where we've bothered to establish habitation. We've changed the Earth so much that we're disturbing global climate patterns, and now we're talking about large-scale engineering work to counteract those disturbances. If I choose to, there are ready transportation networks that will get me pretty much anywhere on Earth, and ready networks for supplying me with food, healthcare and entertainment on all the planet's continents (though admittedly Antarctica is probably a bit tricky from a tourist's point of view).