Fayrazzled, the thrust of my concern is that young women should have a balanced view. In other words, feel free to aim high but be aware that you might end up shooting lower (career-wise) to reach the balance of family and work life that is unique to you at any point in your life.
No young woman would know what is the satisfactory balance of life for her until she crosses that bridge.
You and I would not be happy working 75 hours a week with frequent travel, and I cannot think of many men who would be either. That is just the stereotypical example of a high octane City career. Outside and even within the City, there are lots of medium-octane jobs, say in the £50-80K mark which is family friendly, that you can downgrade to from a £150-250K full on 75hr City job.
It is not easy to find these jobs, they are often not advertised externally, and need to be chiselled out by careful research and networking. But any bright young thing who post-baby applies her ferocious focus to finding that elusive pt medium octane job would get there at some stage.
I can only speak as an ex-City lawyer but I know that in law, it can be done.
Even the commentator in the first link said she went from a leading City firm to owning her own law firm, presumably for more control over her hours (amongst other things). I would bet good money that her fabulous experience and training, pedigree legal background and contacts in her previous City job would have helped greatly for her to make that bold step.
I personally would rather my dd shoot for the stars at the outset (as you did) and then adjust expectations career-wise downward at a later stage. This is contrasted with starting with a mummy job and finding that her childcare options are unsatisfactory because of the low pay, resulting in her having to give up work completely. Thus aiming for a mummy-friendly lifestyle is a self-fulfilling prophecy that too many women unwittingly find themselves in.
If my dd wanted to then give it all up to become a SAHM, that is also available to her. She does not need additional training or experience to do that.
Hence, I would not cut down my dd's ambitions, beyond mentioning that she might have difficult choices ahead of her if she does decide to have children - but that would be obvious anyway from my choice and countless other women around her. Who knows, she might even enjoy 75 hr weeks ...