Short answer: fentanyl is cheap. Wholesale price of fentanyl is around $50,000/kg which is about 400,000 doses, or 12.5 cents per dose. Street value is around $2/dose (~2.5mg). There are a lot of users within that distribution chain who can profit enough to sustain their own addictions.
Humanity is benefited by space. Getting to space from Earth is very hard because of Earth's gravity well. The Moon sits at the rim of Earth's gravity well and getting to space from the Moon is comparatively much easier, saving about 97% of the energy that it would take to launch the same mass from Earth. Resources such as water can be mined on the Moon to be turned into rocket fuel (Liquid Hydrogen + Liquid Oxygen). The Moon is therefore an excellent staging ground for humanity to get a foothold in space, enabling bigger spacecraft, longer missions, and much much more activity in space. Humanity needs to expand beyond Earth for its own benefit. The Moon is the first stop to getting there.