1). We can’t afford to keep paying an ever increasing number of people not to work.
People aren't being 'paid not to work'. People suffering from illness or disability are given subsistence money, and also they are part of the 'we' because everyone, working or not, pays tax.
2) we need to work out what is making our population dramatically sicker and address that quickly.
The cost of living crisis and resulting increased poverty (and also the punitive benefits system) affects mental wellbeing and physical health.
Long and growing NHS secondary care wait lists, and increasing difficulties accessing a GP. What might initially be something fairly easily and quickly treatable becomes something more serious by the time it's seen by the right person.
The poor state of social care and other public services. People aren't getting timely or effective support.
Increased state pension age. People no longer in good health who would've been getting a pension but now have to claim sickness benefit. There's also a knock on effect on youth unemployment. More people retiring at an older age means less vacancies for younger people.
3) we need to ask the sick what needs to be put in place for them to work.
Sort out 1) and 2) and also look at the hiring practices of businesses. Many are unwilling to hire or keep on people with illnesses and disabilities. Many sick and disabled people need flexibility and adjustments in the workplace. The opposite is often the case (like policies around maximum days sick leave).
Another question however is, where are the jobs?
916,000 vacancies, but over 1 million job seekers. So there's not even enough jobs for everyone on job seekers, let alone people on sickness benefits.