The proportion of older persons is increasing in developed and developing countries: this aging trend can be viewed as a two-edged sword. On the one hand, it represents remarkable successes regarding advances in health care; and on the other hand, it represents a considerable challenge for health systems to meet growing demand. A growing disequilibrium between supply and demand may be particularly challenging within publicly funding health systems that 'guarantee' services to eligible populations. Rehabilitation, including physical therapy, is a service that if provided in a timely manner, can maximize function and mobility for older persons, which may in turn optimize efficiency and effectiveness of overall health care systems. However, physical therapy services are not considered an insured service under the legislative framework of the Canadian health system, and as such, a complex public/private mix of funding and delivery has emerged. In this article, we explore the consequences of a public/private mix of physical therapy on timely access to services, and use the World Health Organization (WHO) health system performance framework to assess the extent to which the emerging system influences the goal of aggregated and equitable health. Overall, we argue that a shift to a public/private mix may not have positive influences at the population level, and that innovative approaches to deliver services would be desirable to strengthening rather than weaken the publicly funded system. We signal that strategies aimed at scaling up rehabilitation interventions are required in order to improve health outcomes in an evolving global aging society.