Does that mean that unless a planet has humanoids intelligence and toolmaking is impossible? No, the humanoid body plan has worked out fairly well for us, but that doesn't mean it is a prerequisite for sentient technology.

For that matter, we don't even know if the rise of technical social sentience is a natural development, or just a fluke. Intelligence hasn't been around for long enough to have proven itself as a survival advantage, and it has only ocurred in one species here, late in the planet's history. That argues against the convergent evolution suggestion.

I suspect that intelligence and toolmaking may give a species an edge, but it may also be destabilizing to the biosphere as a whole. Intelligence without technology (as in whales) may, in the long run, be the optimum survival strategy.

Man's impact on this planet was minimal until he invented fire. That technology opened the way for the deliberate alteration of brushlands through burnoff to increase biodiversity and new growth, as well as greatly increasing the chances of totally uncontrolled and destructive accidental fires.

Other technologies, like stone tools, basket weaving to carry produce, clothing and shelter making, made it easier for individuals or bands to live better, but burning off scrubland to produce grassland (as happened in Australia) not only produces a more hospitable habitat for Man, it totally alters the habitat for everything else.