Earlier quoted context omitted.
"Swat Teams" of vetted talent to handle the most prized assets and initiatives. Let the cruft keep up day to day, apply proven talent to the most important initiatives piece by piece. ie. Apple and the iMac, then iPod, iBook, iWorks, Final Cut etc etc.
I actually work in exactly this type of swat team. We were all hired at well above standard payrates at my large company to build the next generation product. The response from the existing teams was immediate - they saw us as a threat, and started doing everything they could to make our project fail. In the end they succeeded in gimping the product by simply giving us interfaces that just couldn't do what a good pro…
Or you need to be actively shielded. I was part of such a swat team for internal tools in my first job out of university. The IT department did everything possible to kill us, get us fired, etc. We needed support from the CEO down to stay alive. In the days before I came on board, our managers and directors would disguise the team, telling other people, "Ah, they're just business analysts working on miscellaneous stuff. Not important. Ignore them."