[clcaev]

I think missing a "window of opportunity" with kids "never learning to sleep by themselves" is dubious. Those approaching adolescence develop quite strong need for personal space, eventually. They start rejecting parental company, instead preferring to be alone or be with their peers.

I have one data point to share. An eight year old child decided one day, rather abruptly, that they were "done" with cosleeping and wanted to be in their own room, in their own bed, by themselves. And that was that.