Anecdotally, a lot of my friends either chose not to have kids even though they were financially able to do so, or 'only' had one kid later in life after they checked a bunch of life goals off their list. And of course there's a segment of friends who never found anyone to partner with.
Furthermore, it feels like the checklist in what people are looking for in a life partner is more complicated now than ever, which can increase the amount of time it takes for a person to find a partner to have a child with. I assume that's a good thing as it may reduce the likelihood of divorce by resulting in a more ideal match, but it potentially comes at a cost of spending TONS of time filtering via messaging, dates, etc. It took me a whopping five years before meeting someone online that actually felt like something with a real future.