@Ideasplease322
I'm not sure who you are asking about the stepping down. Do you mean how it looks in the workplace or how it works financially? Either is going to look very different for different people in different workplace and personal and financial contexts.
Workplaces vary so much. Many don't work like a ladder past a certain point, and if you get creative you can go sideways into other opportunities to create a life that suits you. Over the course of your career it may be more portfolio. People do this all the time, forced by circumstances, including children, health, other caring responsibilities. It does not have to be dissatisfying, in fact it can be overall more satisfying to honour all parts of yourself if you feel that is compromised by imbalance for you. You can step back up later. Someone I know, who left the London City for rural NI, but maintained a portfolio career, is now on the board at Lloyd's. She balanced her career across her life, and is grateful she and her children got to spend a lot of precious time with her mother before her mothers sudden death. As a family, they are amongst the soundest and most well balanced I know. Not perfect (who is) but overall good choices imo. I rate and respect their life advice.
In financial terms, people make changes and cope with different financial levels all the time. This year will be a case in point for many many people in terms of income instability and fluctuations. Divorce often precipitates big financial changes, and people get on with that. Some people do manage to largely avoid lifestyle creep, and don't load themselves with financial responsibility. Or are prepared to cut their cloth if they decide to. Others never got past the childcare cost and can balance by losing it and other changes. Others, dare I say it, actively plan for this scenario and have a strategy to earn lots early then gear shift later when particular financial goals are met. Development of passive income.
Some have independent wealth. Some get unexpected inheritance. Some have wealthy partners. There are so many possible answers here. Not everyone is constantly seeking more more more material wealth. Some are fortunate enough to have "enough" (and again this is personal, people are genuinely satisfied with different levels past a basic level of comfy, and then start valuing other life rewards like time much more highly than greater remuneration). It is so personal, this is really too non-specific a question to answer well.
And of course personal context is vital. Do you have a partner? Do they earn highly or want to be a SAHD, or go more part time/flexi themselves? Do you have a highly involved grandparent? Do you have a secret yearning to live in another cheaper country? And of course opportunities to move vary hugely by sector.
I guess I would probably overall not frame it as a "step down" as i think that is unhelpful. Better to see it as a "step into" a different way of living, and embracing that period of your life. I think rigid hierarchies and career structures are probably a bit passe now, with such long working lives. The period of early childhood when you have a family, and the slow transition into retirement (I don't see that as reaching a peak then hitting a cliff edge retirement, this can be a really challenging picture to embrace). Many very demanding jobs are unsustainable long term.