It's quite a lot more than a year - in primary care, it's more like four additional years of training for physicians, and 15000 supervised clinical hours for physicians (vs 500 to 1500 hours for NPs). The gap can be wider in other physician specialties, because many have longer residencies than the primary care programs. For example, child psychiatry training is four to five years (depending on the route you take), making it longer than the three years of family practice residency.

Here's a chart looking at training for MDs vs NPs in primary care. It is from a physician organization. https://www.tafp.org/media/advocacy/scope-education.pdf