The only reason fossil fuels are "economically viable" is because we're ignoring the cost of the destruction they will bring in the future, and are already causing today. Nuclear is economically viable. We already have lots of nuclear power. Maybe it's a bit less profitable than fossil, maybe if we invested more into it it would be more profitable. Either way it seems entirely viable to me, except of course for all the trillions of dollars being made by extracting and selling fossil fuels to the detriment of all our futures. The only reason alternatives aren't "viable" is because they're priced out by fossil fuels. Take fossil fuels out of the equation and lots of new things become viable.
How is dumping SiO2 into the atmosphere economically viable? How do you make money doing that? If you're thinking that governments should pay private companies to do it, why can't governments simply pay private companies to produce clean power instead? Without having done any actual research on this topic, I suspect you might find that this would be far more "economically viable" than paying for the experimental climate engineering that might not even work, and might have devastating unintended consequences. For example I imagine shitloads of fine sand in the atmosphere would be a problem for aviation, and that's probably far from the only issue with it.
How is dumping SiO2 into the atmosphere economically viable? How do you make money doing that? If you're thinking that governments should pay private companies to do it, why can't governments simply pay private companies to produce clean power instead? Without having done any actual research on this topic, I suspect you might find that this would be far more "economically viable" than paying for the experimental climate engineering that might not even work, and might have devastating unintended consequences. For example I imagine shitloads of fine sand in the atmosphere would be a problem for aviation, and that's probably far from the only issue with it.