Easiest way to make $1 million dollars? Call Elon's bluff. Bet Elon Musk $1M he never reaches mars inside his publicly announced timeframe of 5 to 10 years.
Who is stupid enough to give odds on that? You find them, and we'll pool together the money. 1:10,000 odds means $100 gets a million!
Seriously though, we have no idea what global events will happen this year, much less five to ten. (In fact, I doubt we'll make ten). Elon could be deported to Europe (Canada won't take him!) and lose all access to US launch facilities. Elon may announce an illegal droid police force to run down the "unprecedented" threats against the US. Most likely a minor conflict will accelerate the Kessler disaster and humanity will never get out of LEO again.
The next place humanity is going will be more habitable and easier to get to than Mars - the Arctic. While I don't see US troops invading Canada from the south, I think the US will start probing our resources and there will be nothing we could do about it. :/
Elon will run out of money soon. Countries are cancelling Starlink contracts, his XAI is bound by ethic restrictions, and Tesla is a vehicle for perverts and pride members. (No wonder it has tinted windows and bulletproof glass lol).
Humanity will never reach Mars, with or without Elon. Karma simply will not let us destroy another planet.