I seem to explain the problems with Windows PCs all too often to laypeople.
This may be obvious to IT industry folks, but the reason that Microsoft is failing is because of the high number of security incidents on Windows PCs that require the user to reload their system resulting in a higher cost of ownership, lost work time, frustration, lack of trust, possible data loss, potential security risks, and more.
Ultimately, the Windows PCs as we know them have not evolved fast enough to keep up with what is required... reliability for even the most novice of user in the simplest environment (ie. little of no network/IT investment). Most computer users do not have the expertise nor means to build a layered security model to protect their vulnerable Windows PC.
Of course, a lot of factors contribute to this failure, yet, Microsoft has not taken the steps required to plug the holes. Hence, people are jumping ship. Macs, the cloud, thin clients, SaaS, Linux, etc... the threats to Microsoft's stature are real and the ship has begun to sink.
Can Microsoft retain its dominance, restore trust, and compete with all of the threats? In the long term... no.
The Windows PC as we know it is an endangered species that will be coveted by few. A new mixed breed of PC will evolve that promises a simpler and more reliable computing experience...
