How many people do you know who have been with the same organization for 5 years? 10 years? I don't know if it's even possible to stay with one company your entire career anymore. If you're a top performer, employers obviously want you to stick around as long as possible. But the modern job market does not encourage us to stay on one company's payroll and climb rung-by-rung up a single organization's ladder. Developing your career is now more like climbing Everest in a blizzard. You can't necessarily see where you're going and you've made a few mistakes, but you made the ambitious choice to climb. You're going to keep climbing towards the summit because failure is not an option.
Sorry if you still want the ladder, it certainly sounds much easier. And for a lucky few, it may still exist, but if the corporate ladder isn't working for you, and your career needs a Sherpa to help you climb higher up in the new corporate model, just consider treating your career as a grand experiment. You might think of your career as if you are the product, where each foray into something new is just sending Product You through iterations and testing. Pretend your career is like Gmail, with its extensive 5 year beta period. You may think you're a great marketer, but will you know the truth if you don't try out your hypothesis? Like any experiment, sometimes you'll try something that doesn't work out. Just draw the right conclusions and move on. Hopefully your testing of different careers paths will show you the best way to the summit.