Almost everything.

Here's an experiment you can try. Stay up for two nights in a row. Have a few drinks. Put on a pair of ear defenders, a pair of glasses with the wrong prescription and a pair of leather gardening gloves. Try to go about your daily life. You'll very quickly see plenty of industries that are ripe for disruption.

The man-made world is overwhelmingly designed by and for the not-yet-disabled. We build overly complex interfaces with too many options and too few affordances. This makes life difficult for everyone, but it can totally exclude people with impairments.

Nobody realised how awful smartphones were until the iPhone arrived. I think that most products and services are just as awful as a Windows Mobile phone circa 2005, but we have become inured to their awfulness. We're drowning in unnecessary complexity, in large part because we don't expect anything better.

Health issues begin to interfere increasingly with opportunities to make new friends--there are increasing numbers of activities that you simply can't do anymore. Isolation increasingly becomes a problem, and isolation is a serious health hazard for older people, affecting mental health and posing a hazard to physical health.

Platforms that make it easier for older people to stay in touch with one another, to meet new people safely, and to develop networks of trust and assistance could make a huge difference in the quality of people's lives.