This is probably too long and more for Elon, but I'll write anyway.
We should practice on the Moon first even if final destination is on Mars:
1: Emergency life support system for Moon base: O2 bottles, CO2 scrubbers and Lithium batteries for energy. All these for two weeks. Space ship on Earth ready to get to the moon in two weeks. This is not possible for Mars base. If everybody dies on Mars base, when can we try again? In 50 years? That could be too late.
2: Inhabitants of
Biosphere 2 - Wikipedia had too much work in maintaining their greenhouse. On Moon base lot of work could be done by remote control from Earth or by automatic systems monitored from Earth. So size of maintenance and building grew on a Moon base is much smaller, perhaps only 10% of Mars base. First Mars base can have tech version 2 and save more money than was used for Moon base.
3: I don't see how Mars base could generate income, except by reality TV videos for few years. Moon base can have hotel Moon. When base can manufacture metal, they can build radio telescopes on the back side of the Moon. Moon will protect from radio noise and astronomers have access to all frequencies instead of narrow gaps
radioastronomy - frequencies list We can manufacture 8.4 m optical mirrors on Earth. Those must be thick and heavy not to bend and crack under own weight. Mirrors made on Moon could be thin and light. Perhaps mirrors could be made mostly by remote control. Earth needs many large telescopes to observer all these in time:
News | Small Asteroid or Comet 'Visits' from Beyond the Solar System
4: If something goes wrong on first attempt, Moon base will save time.
