Empirically, "tech not actually possible" is a relatively rare reason for startups to fail. Other reasons are much more common. So putting a lot of effort into

Empirically, "tech not actually possible" is a relatively rare reason for startups to fail. Other reasons are much more common. So putting a lot of effort into verifying this doesn't affect an investor's return much. Also, a common trajectory is shooting for something impossible, but discovering possible and useful things along the way which turn into great businesses. So even if you're 100% sure the idea is impossible, it might still be a good investment.