I think by the time I retire (2070?) Americans of 95th percentile wealth will mostly choose to retire on orbit. IE engineers and modestly successful doctors, not just Elysium billionaires. I would bet the first (very rich) retiree will permanently move to orbit by 2040.

This might sound like I'm poking fun at old people but this is a product I genuinely want for myself. The arguments are that Earth gravity is awful when your body's failing, retirement home residents rarely leave so expensive transit is OK, the cancer risks don't matter when your life expectancy is already under 20 years, and the best homes in the best places on Earth can't hold a candle to a 600,000 foot view.

Health Questions

The critical question is what sustained partial gravity does to human bodies. We know microgravity is quite bad, and we're very familiar with 1G, but other than a few people spending a few days on the moon we don't have any long duration data points between 0 and 1. I'm pretty optimistic about partial gravity because the loads on human bodies in 1G already vary so much: the heart, lungs, and joints of an obese man see wildly different loads than those of a petite woman. It's easy to understand how the complete lack of a gravity vector would break even the most resilient systems, but an 80% weaker one seems far less challenging.

If humans need 1G to thrive, this whole idea is likely dead. A 1G orbital retirement home is a harder version of a cruise ship retirement home, which exist but don't hold mass market appeal.

However, if I'm right and it's safe I think everyone will aspire to retire in low acceleration locales. Falls are a major cause of death for the elderly, and putting them in 0.2G would largely eliminate the issue. Reduced gravity might also reduce stress on the cardiovascular system which is the leading cause of death. Beyond talk of death, making everything in your daily life 5x lighter would do wonders for independence as would the lower forces on arthritic joints.

My generation's choice as we approach 80 may be between life in a power chair depending on family to care for us, or an independent life bounding down corridors between old folk LAN parties, billion-dollar Earth overlook views, and perfectly manicured little terrariums in totally climate controlled chambers.

Launch Questions

I've toyed around with flight simulators a bit, and it looks like SpaceX's Starship should be able to reach LEO with a small payload (say, 20 septuagenarians in crash couches, plus a couple nurses) without exceeding 2.5Gs of acceleration. That's endurable for all but the most fragile passengers, and future launchers will only lower the stresses of launch.

I also suspect launch cost economics guarantee these homes would be less isolated than they initially sound. The mass required to build and support these homes puts a ceiling on the launch prices which can support them, and although I haven't sketched out a financial model I think occasional (major holidays?) visits from family would be very cheap relative to the station construction. There are interesting factors that could change this, eg if most station mass comes from lunar mass drivers not terrestrial rockets, but in general you need a combination of high self sufficiency on orbit and high launch costs for orbital retirement to be much more isolating than current retirement. Self sufficiency is very hard without an enormous mass budget, so barring weird stuff like self-replicating fully robotic lunar mining I think my grandkids will visit me.

Aesthetic Appeal

My inflatable structures ideas are the discount version of an O'Neill cylinder. I'm hopeful we'll have full on cylinders by my retirement, but the premium-mediocre option here is a more conventional station design with a tether and counterweight for spin gravity.

In sufficiently weak gravity swimming and flight converge. An average human swimmer could swim up from the deep end and breach like a whale, sailing through the air before landing in an enormous slow motion splash in lunar gravity. You could also dive to five times the depth without painful ear pressure in 0.2G. The rock climbers and gymnasts among us will appreciate the freedom to leap from grip to grip long after our bones and connective tissues would give up in Earth gyms. The asthmatic among us might breathe freely for the first time in a dust, smog, and pollen free medium, and everyone else will enjoy perfect climate control as a free side-effect of life support systems.

These are unlikely to be lonely places. Life support systems and resupply shipments both enjoy returns to scale, so we may see a handful of retiree megalopolis cities on orbit instead of a fleet of typical scale homes lobbed up the gravity well. If we really knock space industrialization out of the park these cities can have large scale parks.

Humans aren't the only organisms I expect to thrive in partial gravity. Earth tree heights are limited by the balance between capillary action and gravity - redwoods stop growing when they can no longer lift water to their crown. The generation after mine could enjoy thousand foot forests in their partial gravity homes on orbit, Mars, or the moon. I'm excited for us to discover the engineering limits of topiary using transgenic plants in hyperbaric controlled atmospheres.

Speaking of transgenics, I can't imagine a safer place to toy with the code of life itself than a completely sealed park in a space city gliding through the vacuum of space. I love fireflies, and I'd like them to be brighter with a broader spectrum of colors. This might sound off topic but I'm imagining a vibrant future for the traditional 'granny garden' in high orbit.

Coda

The details of this post are almost certainly wrong, but I think the broadest strokes are right. The trajectories of space-based manufacturing and SpaceX's cost per kilogram to orbit suggest private industry will be able to fund and operate large commercial space stations in the not too distant future, and people will go when it's cheap. Life on orbit will be better than life on Earth for almost everyone, but particularly for the old and frail.