I don't think it gets easier, it just keeps getting different.
I'm in the minority saying that on here, most people reassure that it gets easier after 6 weeks, or maybe a few months, definitely by a year. It's nice to be reassuring, but I feel that it lets down the many mums who don't feel that it gets easier, and that they were fed a lie to get them through whatever time it was.
Maybe it does gets easier eventually if you have very straightforward kids. I don't, so wouldn't know. The thing is, a surprisingly large number of kids fall into the non straightforward category. So for those whose kids start to sleep at a 'normal' age, who makes friends well, behave well, do well at a school that they are eager to go to, I imagine it does get easier.
For many sleep is still dire in toddlerhood/preschool years, and the incredibly demanding nature of toddlers means that for many it's the most demanding time. Being honest, it made looking after a newborn like looking after a houseplant in comparison. Both of my children slept worse at 12 months than 12 days or 12 weeks.
I thought it would get easier, at school age, and it does have plusses now at 6&8. Their independence has increased (not as much as usual though due to disability and Sen). They now can play for half an hour, maybe an hour independently. All good. But their issues are harder to resolve. It's not simple needs any more. It's battling schools to get support, it's reassuring my child about their future. It's sitting there whilst they sob about a friendship issue. It's dealing with bullying for disability and being different. And they still don't sleep well, only this time they can follow you around getting upset...
For kids without those sorts of issues you can skip a lot of that, and maybe babyhood is the hardest it gets, and they are very lucky.
I mean, things are different. They are no longer only napping for precisely 37 minutes. They no longer poo the second we leave the house then demand milk. We no longer make drives longer so they stay asleep. But as those challenges went, they were replaced.
I think what changes is we get used to life being really hard, having no time to ourselves etc, so it doesn't feel like such a sacrifice any more.