We have been fortifying food as a response to the fact that pregnant women aren't uniformly getting enough folic acid. Downplaying prenatal folic acid supplements is like saying we don't need to worry about driving safely because people have added seat belts to cars. (One could imagine safety equipment that is so good we don't need to worry about how well we drive, but we're not there yet.)
https://www.webmd.com/baby/folic-acid-and-pregnancy#1
We have been fortifying food as a response to the fact that pregnant women aren't uniformly getting enough folic acid. Downplaying prenatal folic acid supplements is like saying we don't need to worry about driving safely because people have added seat belts to cars. (One could imagine safety equipment that is so good we don't need to worry about how well we drive, but we're not there yet.)