2) To be replaced by endless after school activities/sports, events, and other child-related things. Fine if you like them, but if not you're not seriously getting your free time back until maybe the teenage years. A decade+ in the prime of your life is not a "mere blip" to many.
3) You do (which is great - clearly you're the sort of person who should have kids). There are a lot of people who have children and....don't suddenly find an appreciation for children. The vast number of children in the world with a willfully absent, abusive, or simply disinterested and not loving parent stand as a clear counter-argument, and the statistics on child abuse/neglect are pretty awful.
On the anecdotal side - It's pretty heartbreaking how many of those I grew up with (who had outwardly normal, upper middle class families) turned out to have those sorts of terrible parents and traumatic childhoods...and those are just the ones I know about. I'm thankful I didn't have that childhood, but a shocking number of children do.
I think it's misleading to promote this ideal like it's just going to happen for everyone who has kids and leads to people who shouldn't have children having them and resenting them or worse.