It's about returns to worker productivity. As the article mentions, factory workers are hundreds of times more productive than they were in the 1960s. They are probably thousands of times more productive than they were in the 1760s.
How much has worker productivity increased in, say, symphonic music? In the last 300 years, I would guess it has perhaps doubled, if that (amplification) And yet symphonic concerts still happen, despite costs increasing without bound!
Medical costs rise because new services are available, but worker productivity rises slowly. Medicine may be a larger and larger fraction of the economy, but as long as worker productivity rises in OTHER fields, we will still be able to afford it.