We had the technology to start. Photovoltaic panels, windmills, etc aren't new technology; the Carter administration actually installed photovoltaics on the white house and they stayed there until three guesses which president (yep, Reagan) took them down. Florida voted to start building a high speed rail project in their state (which would have decreased interstate and short-haul airline dependency, thereby decreasing oil dependency) and it was going to happen until Mr. State's Rights himself, Ronald Reagan, blocked any state from launching a high speed rail initiative. More people believed in global warming and climate change in the 90's than now, but in the 2000's, the small government W Bush administration forbade government officials from talking about climate change, gutted government research on climate change, and collaborated with big oil lobbyists on pivoting to using softer, more nebulous terms to address global warming (this is actually where the widespread use of 'climate change' comes from). We've basically kicked the can down the road for forty years and only started taking it kinda seriously in the last ten or fifteen. If we'd been developing and implementing these technologies gradually over the last fifty years, it would have been a lot less painful and we'd have made a lot more progress for a lot more value on the money spent. Since we're trying to speedrun the last fifty years of implementation and development into the last decade or so, that's going to be really economically painful and not nearly as smooth as it would have been under the long implementation. But, it's gotta get done, or we're going to keep fucking up the same ecology we depend on to stay alive, getting in endless wars, and giving money to jackass countries to feed our voluntary fossil fuel addiction.

As for storage, that's not an unsolvable problem. Probably the most practical solution is a nuclear fission backbone, imo, but there's several approaches that are in various stages of development and viability.