Comment by hibikir

Because fast to deploy in theory fights quickly with permitting systems and NIMBYism. You need more permits, because a typical solar or wind farm doesn't come close to a nuclear plan's output, so the per-project bureaucracy multiplies. By needing more places, you also have more groups opposing projects for typical NIMBY reasons. You need battery facilities too, and more updates to the grid to deal with having less inertia, and the updates cost money, and the battery facilities themselves face more NIMBYism: Minimum distances to places where people live and such. So when you put it all together, slow bureaucracies just move at glacial paces, and the equipment you would have bought when you sent out the permit is already different than what you want to use when the permitting is approved.

Then we have the tariffs, as Europe puts tariffs on Chinese equipment that change the price quite a bit.

A country that took this very seriously and decided to put renewables as a top priority could go quite fast. But if there's anything one should learn about the last few decades is that modern democracies care too much about vested interest and NIMBY complaints to actually get projects like this done. Just look at charts showing power waiting to go online in most countries: You'll find very long lines, even after dealing with the rest of the the bureaucratic gauntlet.