No one wants to try nuclear for reals because people are frightened of it and world governments don't have an economic interest in building more nuclear.
We don't have an equivalent of an "operation warp speed" for developing next-gen CO2 scrubbing technology. I guess that's just not as cool to people as building tunnels under LA or launching cars into space.
Speaking of algae, we're not turning wasteland into algae farming ponds and developing more useful algae because, well, I don't really know. Even with CRISPR-Cas9 being in relative infancy, GMO algae seems like a low hanging fruit for not only removing carbon from the atmosphere but being a food source in places around the world where food is scarce. I mean, as an individual you can buy a kit that has what you need to genetically modify yeast to glow with jellyfish genes, so how far off are we from making species like chlorella more practical? Maybe it's because nobody wants to eat pond scum.
All I know is that the amount of effort we are putting into these solutions, although there is some effort in each of them, really doesn't add up to the message we are being told about climate change. It's both extremely disappointing and cause for raised eyebrows.