Depends on whether you wish to calculate the extra costs that burning fossil fuels has on the climate/environment. If not no other source will be more profitable the coming decades. I in generaly am pro capitalism but willingly destroying your own planet for a few bugs is something I will never understand. Its not like sustainable energy isn't profitable these days its just less profitable from purely an economical point of view.
That contradiction is Marxist theory right there.
Basically, the mechanisms that feed capitalism are also what destroys it - and the unfortunate thing, it's taking the world with it. As a world we really should be doing all we can to protect the environment and the sustainability of resources. It's logical to move to a green/sustainable economy right now - the technology is already there.
Funny thing is though that every communist country or someone who tried to make a country communist are usually among the worst poluters out there. The problem with communism is that innovation is not rewarded. In general we do need stronger and better governments environment ministers/agency. The market even asks for it.
Capitalism actually holds a lot of great values and is a very decent starting point. However our current capitalist lineair consumptie economy needs to be steered towards a green circular economy and partially controlled to really be benificial for the well being of people, planet and profit and should not only run on profit. Although the latter is neccesary.
Unfortunately our governments are getting more and more like companies and will not act if a plan is not profitable enough. I see it in my work all to often it a plan does lots of good for the planet and the health of people, but is not profitable enough governments and companies in general will not invest into it.