No, this trend started over a decade ago. Here are some possible explanations from the article:
Some of the reductions are easy to explain. Congress changed Medicare policy. The biggest such shift came with the Affordable Care Act in 2010, which reduced Medicare’s payments to hospitals and to health insurers that offered private Medicare Advantage plans. Congress also cut Medicare payments as part of a budget deal in 2011.
…
Older Americans appear to be having fewer heart attacks and strokes, the likely result of effective cholesterol and blood pressure medicines that became cheap and widely used in recent years, according to research from Professor Cutler and colleagues. And drug makers and surgeons haven’t developed as many new blockbuster treatments recently — there has been no new Prozac or angioplasty to drive up spending. (Medicare is currently barred by statute from covering the new class of expensive anti-obesity drugs.)
Parts of the health system appear to have become more efficient, as medical providers have been more cautious about adopting new therapies without much evidence, and more care has shifted outside hospitals into cheaper settings.