Nations are able to afford it with a healthy dependency ratio, but with the Baby Boom generation leaving the workforce, it will no longer be possible.
A young family who have recently migrated are saving for a house and college, to make them pay for a decade of end-to-life treatment (cancer treatment, dialysis) at United States price ranges is unaffordable even for very high income earners.
Remember the two parents have four grandparents, and two children (the receiving country would love for them to have a third).
That said, I am open to a special visa with a million dollar escrowed deposit per elderly parent to cover their healthcare. Without extreme restrictions they are bound to become a healthcare burden on the system.