Renewable energy cannot compete directly with that. For some rough numbers, you'd expect about 150 hours of usable sunshine a month (depending where you are), so to generate a barrel of oil worth of power per month, you'd need around 10 kW of solar panels, which will cost around ....maybe $35,000 to build. (Then add a few more $k for batteries, controllers, whatever...)
These numbers are super rough, and vary a lot, but just as a general order of magnitude thing, obviously it's better to pay $10 to pump a barrel of oil out of the ground every month than it is to pay $35-40k upfront to build a solar system that generates the same power; it'd take centuries for the solar system to even break even (and it's only going to last decades).
BUT. We're obviously running out of oil in general, and cheap oil in particular, and the cost of solar power is dropping fast. And also, while it would be extremely expensive (today, at least) to switch to solar and other renewables for everything, it's a thing we can do. And by the time we really will have to do it, it may not even be that expensive. And if you factor in the impact of carbon, the numbers start to look more even.
> If it was such a great investment, wouldn't everyone be running to install it more or less?
A lot of solar is being installed; for a variety of reasons domestic rooftop installations don't tend to make a lot of sense (you didn't have a coal power plant driving a steam turbine in your basement either), but that doesn't mean all solar is un-economical.
But no, it's not an amazing investment yet. But it is feasible. The comic essentially suggested that we're squandering our only chance to live beyond the power of human muscles, and that's far from true. And given the cost curve on solar panels, it's not even clear we're being too slow to make the switch.
