I mean, sure, people who have no kids and decide to really dedicate themselves to a career are a thing.
And tbh I think they deserve to have that recognised with things like promotion. I go home, for the most part, at the end of my workday, on ocassion I will end up staying longer because i'm a manager and that's part of the job, but I have four kids and other things I like to do too, I'm not spending a ton of extra hours at work.
I don't expect my team to stay late either, they aren't that well paid and also have lives. I try hard to manage their time so they can take care of their other responsibilities too. However - I do recognise that some of them do go above and beyond and have special dedication - most (not all) of those do not in fact have kids.
I think sometimes that can come off as unfair when these people get promoted or special jobs or courses, and there is a balance to be had. Before I was a manager, there was a woman on the team I was working on who had been in the job many years. She wan't to move into a differernt position - almost a lateral move although pay was a bit more, but she wanted to go from working with the public to a behind the scenes job, in large part because the clientele had changed and she wasn't really keen on man of the new people who were a more challenging population.
She didn't get the position, it went to another internal applicant who hadn't been there as long, and caused some bad feeling, including amng some of the other older team members.
I think the differernce was, the older woman, although conscientious and competent, had always treated it as just a job, and had been clear she stayed mainly for extra health insurance as she had a family member with a serious health condition - (a family member who wouldn't need that insurance for many more years.) All perfectly good reasons to have a job.
The young women who was chose instead, otoh, clearly intended it as a career or even a vocation and had pursued extra education to that end. She was likely to stay for many more years in the role and eventually would be a good candidate to lead her technical team. I later, as a manager, had an interesting discussion with one of the other team members who had felt this was an unfair decision. She hadn't actually even considered the longer term planning elements, or the fact that the younger woman likely would have left eventually without a chance to move up, in a place where her education wasn't especially common. So my team member had been quite annoyed because she wasn't really thinking about the bigger picture for the workplace.