Yup, I noticed. But I couldn't wait that long!!!
Impatient, I am...
(Why did it take that long?)
Anyway, on another subject, I say that we balance the cost-benefits of doing some of the raw material processing at source (e.g. moon), where gravity helps with some things[1], and lets you launch less mess (or "more useful stuff" for any given launch mass) via your mass-drivers, with all the useful stuff that can be done in space, away from lunar electrostatic dust contamination, etc...
Sending up completed girders is probably not what you want to do, if you don't want to risk damaging the end product during launch. OTOH, I wouldn't just pack up regolith and fire it up. There'd be a median point where it's best to take a part-processed set of materials and send it orbitwise for finalising, though. (Exactly where, I wouldn't want to say... Greater minds than mine will be working that out, once the possibilities actually exist to be quantified, refining the guesses they've probably already made after extensively studying the hypotheticals we already imagine would apply.)
We'd want people living(/semi-permanently stationed) in orbit of every place that we have people on surface of. (Thus several orbits... apart from Earth orbit that'd be Luna orbit, Mars orbit, perhaps Venus orbit, not sure about Mercury, but if we have people on the surface...) Some of those orbital communities could be on natural satellites (Phobos and/or Deimos) that give significant amount rock to dig into without having too much gravity to get off-moon out of, but otherwise a whole batch of Luna regolith (or waste products from space-smelting?) or asteroidal material could be used to build up around the short term solar flare protection shelter, and perhaps a lighter amount around the living quarters if it really is 'constantly' bad.
Apart from the people in orbit being able to help those on the planet (emergency supply drops), it'd also be nice to have everyone in orbit able to have a fall-back(/down) point to reach a solid surface (and another set of supplies) in case of space-catastrophe. So it would become be an integrated thing, space colonisation. Some people permanently spacers, some people becoming settlers on surfaces of planets/moons. Which will probably involve some disasters, one way or another, but omelettes/eggs, right?
What we are going to need is people who would be willing to be the pioneers. The frontiersmen/women. Supported by governmental or government-scale funding to get them there, of course. That latter part is the sticking point, I think, because there'd be (there are!) loads of people as mad as Ice Road Truckers who'd jump at the chance to go 'out there', but until we have the infrastructure set up to do so in sufficient quantities we're still going to be slow to start doing that.
Global catastrophe time is probably too late. (Unless some government has some secret 'space ark' project sitting hidden under a mountain or something, ready to launch at a few months notice.) Comfortable times won't help either. A steady building of pressures, while there's new methods being developed (SpaceX, etc) that might service an unforeseeable demand... That's what will work, probably.
But I'm waffling now...
[1] Separation of smelting products, although centrifuge-capable smelters in zero G could do the same thing, like a Dyson[2] or a centripetal oil/water seperator does on Earth)
[2] "...vacuum cleaner", not "...sphere".