I well remember the outrage in the Australian business community when laws were changed to mandate certain disability access standards. People building new motels had to have disable accessibe rooms. We built buses that kneel, we have put little driveways as footpaths cross gutters.
All of this seems like an imposition to the able-bodied who fund it.
But the sad truth is that you can become disabled at any time. Cynthis Banham has had that experience, surviving a hoorific plane crash in Indonesia. Today she has written in the SMH of her experience. She and her husband made the necessary rearrangements to their own home, but she expresses eloquently her frustration trying to visit even close family where small doors, inadequate toilet spaces and stairs are impediments to her.
Having had both my father and father-in-law "progress" in life to being wheelchair bound I am personally familiar with these issues. My own house is not perfectly accessible, but it is something I will be correcting over time - especially the entrance.
I'm not sure "universal design" needs to be mandated, but I do think housing and architectural guidelines should be updated and houses given accessibility ratings like the energy rating stars on appliances.
Finally, it is only while writing this that I've realised how particularly dumb is the modern trend to putting the toilet in a separate cubicle rather than as part of the bathroom. It guarantees they are not accessible.