Microsoft CEO Satya Nadella Business Insider Satya Nadella has been CEO of Microsoft for just over two years and has been credited for building a new Microsoft, less focused on Windows, more on cloud; less focused on self-promotion, more on partnerships.

But there's one area that he has been hanging onto, perhaps dangerously so: There's very little fresh blood at the top.

Nadella himself is no outsider. He's been at Microsoft for almost his entire career, since 1992 – or about a quarter of a century.

And the average tenure of the senior leadership team that directly reports to Nadella is 16.7 years by the end of 2016, reports The Information's Steve Nellis.

That's even longer than the average tenure of execs at Apple, which comes in at 12.7 years, reports Nellis. And Apple is known for being run by the old guard.

There's one notable exception: Dealmaker Peggy Johnson who Nadella hired himself in 2014 from Qualcomm in 2014.

And maybe you can toss Microsoft's applications chief, Qi Lu, in the newcomer bucket. He joined Microsoft about 8 years ago, in 2008. However, as we previously reported, there have been times when the quiet, thoughtful Lu has been overshadowed by Microsoft's outspoken head of Windows, Terry Myerson, sources told us. Myerson has been at Microsoft since 1997.

While Nadella is known for getting out in the world and talking to everyone from former hated rivals to startups, there is still danger in surrounding himself with the old guard as key advisors.

It's hard to really a change a culture that way.

And Microsoft's culture has historically been about being its own insular island.

For most of its existence, Microsoft had a strong "not made here" culture, in which Microsoft pursued every new tech field by building its own technology. That's how it got into video games (Xbox, games), enterprise tech (databases, Windows server, Office, cloud computing), devices (PCs, keyboards/mice), advertising (Bing, MSN), and so on.

And while Microsoft was so busy listening to itself and building its own things, the company missed the biggest sea change in the tech industry in the last decade: mobile. It's now got to come up with a new strategy as Windows becomes less and less relevant.