Green technology certainly needed time to mature into a level of efficiency that at least pays back the carbon tax of producing the piece of hardware comprising the renewable energy source, e.g. a solar panel. And as it happens, tech that's more efficient tends to be more profitable.
But to your point, what would have been better is if big oil and other legacy stakeholders did not actively try to fight the transition to green-tech in the form of market-adoption disinformation campaigns and stifling investments into green R&D from as early on as the 1980s. And more recently by lobbying politicians to allow them into more ecologically protected areas.

They have literally paid money to politicians to keep things the same instead of just letting technology evolve the way it would naturally with regard to supply and demand. The problem hasn't really been the capitalist model, imo, it's the people who are morally willing to cut corners to make an extra buck with less effort.