Nokia had a lot of expertise around making hardware, even at the smartphone level, but the article indicates that much of this was unnecessarily tied up by the Symbian faction, meaning that substantial cooperation appears to have been denied to the Linux faction within Nokia. That by itself explains why various hardware problems always seemed to recur with the Internet tablets and why Nokia spokespeople kept telling customers that they couldn't expect Free Software drivers and that they should consider themselves lucky with what they were given.
What we see in this story is probably commonplace in businesses where one product line, responsible for a lot of earlier revenue, is rapidly going out of date but where those in charge of that product line dominate the resources and refuse to relinquish them, insisting that they are "part of the solution". I imagine it was similar with Solaris within Sun Microsystems when customers told the company that they had to modernise their OS distribution and/or provide GNU/Linux in the product line-up: things like OpenSolaris, Sun's Linux distributions, and various modern tools all probably faced internal opposition from the factions insisting that the golden age would return and on their particular schedule, too.
Symbian, competitive in the form of its predecessors in an age when they offered features lacking from certain desktop operating systems, was getting a renaissance from the availability of Qt across all Nokia's platforms, but that was merely a measure to dull the pain of working with it in an age when there are fewer limitations on what you can deploy on a mobile device. Sadly, that helped prolong the mindset that Symbian might be the only answer to the company's problems and thus prolonged the turf wars that undermined the introduction of a viable successor.
Nokia's main problem appears to have been incompetence in management, thus squandering many of the advantages of being a large organisation with access to substantial resources.