My megaproject ideas are mostly pretty standard. I'd build a high speed rail network across North America, and build and expand metro and regional rail systems in and around every city. I'd turn all cities and suburbs into fifteen-minute cities. I'd decommodify housing, and build ten million units of public/social/non-market housing, mostly three bedroom units. I'd link those last three policies together by building TODs around the new Metro and rail stops. And I'd build bicycle networks in every town and city and connect them to the TODs. I'd build bridges and walkways across skyscrapers. I'd put a bidet in every American toilet (uses less water than toilet paper apart from being more comfortable). Fiber internet in every home. A heat pump in every home. An induction stove in every kitchen. Phase out fossil fuels and power everything with Pumped Storage Hydropower and Geothermal. I'd make the US go Metric.
But my truly crazy, obsessive idea would be to bring back the French Revolutionary calendar. Or I'd purge all French influences from English.
Agreed, you'd need an astonishing amount of equipment to do anything up there. Which is why i can't imagine a logistics system on both sides of the gravity well for finished goods ever making sense. Heat shields & parachutes only get you so far when you start scaling up from a several people in a hollow capsule to bulk freight loads. Retrobraking adds a gas tax that scales with the rocket equation.
Any tech you have for making a self-contained, pollution-sequestering factory in orbit could probably be built on the ground a whole lot easier and cheaper. Which is why i dont think we'll end up having orbital factories without a scifi-ass megastructures or nuclear rocket engines & the headaches they bring.
But we'll probably keep slinging shit into orbit for a long time. Panels are cheap & getting lighter. Mirrors are cheaper & lighter still, and can multiply the effect of panels you have. And its all scaleable and implementable with current tech. Yeah, you're never going to off-world all power production with beamed solar this way, but it's a workable vanity project.