He was brought in not only for his expertise but in hopes that he could reform a sclerotic design process that's stuck in the 90s. AMD, Apple and Tesla (places Keller was before Intel) use a lot more design automation and thus are able to get more done/engineer. Intel has a patchwork of tools that are generally internally developed (and thus no one outside of Intel has expertise with those tools and expertise with those tools is not transferrable outside of Intel either) and different design groups have their preferred tools. From what I gather Keller was trying to bring in more industry EDA tools and standardize the design process between groups as well. From what I hear from people who were there he ran into all sorts of push back. So I gather he's decided to cut his losses and leave Intel to languish.
Being around big tech companies for years, for an explanation of what's going on it's easy to guess that maybe at Intel there is a status quo in practice solidly in charge that, in particular, believes that Moore's law is sick if not yet actually dead and, thus, wants to stretch out how much longer Intel can get good revenue with a sick or dead Moore's law.
Then for Keller and Intel, here is a possibility: Have the status quo at Intel bring in Keller and then ignore him so that (i) being at Intel he won't be doing things at a competitor that hurts Intel and its status quo, (ii) being ignored he won't be able to change the status quo at Intel, and (iii) being at Intel and ignored his career will stagnate so that in the future he will be no more threat to the Intel status quo.
That is, maybe the Intel status quo competes with people down the hall -- not the first case of that -- by ignoring them and for a chip architect competes with him by bringing him into Intel so that they can ignore him.
Broadly a new direction for him might be to quit being an employee, e.g., fighting the politics of the status quo, and start being an employer as a CEO of his own startup.
Quite broadly in the US, one of the keys to progress is to have lots of startups to get around whatever organizational dysfunction exists in older companies.
One of the reasons for this situation is the propensity of BoD members to be conservative, that is, risk adverse, to pay attention to the definite and well known bird in the hand, even if it is getting sick, and ignore the not well known and risky birds in the bush. In particular, such a BoD wants a CEO who just does a good job managing the existing business. Typically a BoD won't fire a CEO for failing to get new products into new markets but might fire a CEO who spends $100 million pursuing something new that fails. So, lots of CEOs just stay with the bird in the hand.
Indeed, suppressing upsets to the status quo was always a major purpose of corporate research labs like IBM Watson Labs, same Xerox, Bell, Kodak.
Corporate would spend any amount patenting things, but shelve every single thing. Innovation upsets the gravy train. So as long as you are on top of the market, change is inherently bad. Even a whole new, unrelated product line competes with existing products if a customer for both might be the same company.
A co-worker once sat listening to execs from EMC chatting about competitive threats: uniquely from other divisions of EMC. With 80% margins on existing product, nothing new looks attractive, nothing outside the company is competition, and it doesn't even matter what outsiders hear.
Such a company also benefits from buying up apparently competing companies and disbanding them or jacking up their prices to match. In the '80s, Mentor Graphics's business model depended on buying and shuttering Cadence-like companies. Cadence was the first one too big to do that to, and MG finally had to figure out another business when the gravy train dried up. They collected lots of rent until then, and the managers left flush and found other crooked opportunities.
It's easy to spot other companies in similar positions, past and present.
I find it interesting that (as of this point) comments that speculate on health are downvoted, but comments that speculate on his relationship with management are not...
People tend to empathise with that which is more relevant to their own lives; more people will have a bad relationship with management than bad health.
Why not both? Bad management can lead to bad health. But I don't think it was only management - it was the rank and file that didn't want to change as well. Trying to fight an entrenched system could definitely lead to illness.