Are people who want to have kids really struggling to have them though? Keep in mind that fertility rate is not actually about fertility (not directly at least). It's a measure of the kids being had rather than a measure of the capability that the name would lead people to think.
Ivf is way more frequent then it used to be
Exactly. So since we observe that actual birth rates among women in their 30s displays a different trend than that of women in their 20s, despite decreased natural fertility, there has to be more going on.