Many people f stay in the same career oath their working life. You don't have to change careers to grow. You take promotions, new challenges, new responsibilities. Doctors for instance are often extremely ambitious people. Their success is not hampered by not changing careers. They grow within the medics. Field.
The reality is Yes you are giving up a career. You may be getting a new one, but that doesn't mean you aren't still leaving a career behind.
Honestly if you marry a royal it better be About more than love. You may say you are happy to give up your isn career, freedom And privacy but all marriages have a honeymoon period. Your marriage is not always going to be happy, especially when you have outside stresses. If the only thing that makes you happy is your spouse, you are going to be miserable. There has to be something more.
Are you happy changing careers? Will you be satisfied cutting ribbons? And even then, only part time at best. Are you prepared to spend your free time at home with kids (not everyone dreams of being a stay at home mom). The reality of total hours, it is like being a housewife in the fifties. Your main job is home with the Kids. But you were involved in ladies groups, church, had dinner parties fir your husbands work. In this case though the church groups and dinner parties are royal engagements. The excitement if trooping, Ascot and holidays will wear off.
Honestly I would never. No matter how much I loved the guy. Being Kate would be miserable for me. I didn't spend over eight years in. University to do 200 engagements or so and even those tours and shaking hands. I am a nurse. I need to be taking care of people, and I don't mean as a mom. I don't need to be a royal to make a difference. I likely put in twice as many volunteer hours a year, ontop of a full time job, as royals do.
So yes, for royals as long as there are double standards about working, there will be issues finding spouses in modern times. And the older they wait to marry the harder it will be. The longer a person is working and building their life, the less likely to give it up even for love. Usually when you marry, you build a life by blending with your husband. Nit given up all you are.