We've yet to even land a human being on Mars, and Musk is talking about how his spacecraft will take people well beyond Mars -- to where, one of Jupiter's moons? That's nearly a two-year journey, and we haven't even figured out how to return people to Earth from Mars... so basically it's a suicide mission.
Let's take one step at a time, especially considering that one of Musk's rockets just reminded us that space travel is hard.
The problem with your suggestion is that we if allow a nascent and developing renewable energy industry to compete against an entrenched multi-billion fossil fuel industry that has been receiving trillions of dollars in subsidies worldwide for decades, it is not a fair fight. Just last year, the fossil fuel industry received $5.3 trillion in subsidies, or 6.5% of global GDP, according to a study by the International Monetary Fund.
So the playing field is already uneven, and renewables have to date received a tiny fraction of what the fossil fuel industry has been receiving for decades. At its peak, in 2011, the renewable energy industry worldwide received $88 billion in subsidies.
As we know, or as is obvious, renewables offer the greatest promise for the future of energy. Taking subsidies from the fossil fuel industry and "wisely" investing it in renewables only makes sense.
Divide that by one charge every day for 365 days and that's 275 years of battery life.
The sooner you fall behind, the more time you have to catch up.