Kicad taking over Altium is talking nonsense, because no sane big company would use a tool which is core to their business without contractual support. Now, this is why what they say in the above link makes sense and should be Kicad's team strategic offering and bread and butter. However, if that happens and becomes a success, sure thing it will end up someone making them an offer and the guys cashing the tool out for their retirement tickets and the world will be back to square one.
Or rather, there are a lot of engineers that have 10K hours of experience in AD, and they have built up libraries to use, that also takes a lot of time. Who is going to pay for all the engineers to gain the same experience? Let's say it only takes 1000 hour to be able to use KiCAD almost as effectively, just multiply it with your wage.
Include opportunity cost.
Include prototypes that have to be scrapped because you used a new software and made a mistake.
Libraries are one thing, but KiCAD already allows import of third party libraries (though the process isn't super smooth, it can be scripted - probably an area to improve upon.)
But the idea that you are throwing 1000 hours at learning KiCAD? No, I don't believe so. Most of that effort is getting experienced with a generic PCB layout process, you can apply that to most tools. KiCAD isn't that different to Altium in its basic operations which is what 90% of your time with the tool is spent doing.
Also, if Altium costs ~$10k to license, plus whatever annual maintenance costs there are, then there is a huge opportunity cost on that licensing fee that a megacorp could save on. Even if it means sending engineers away for a refresher course on Altium. We pay our PCB contractor ~$70 USD per hour (GB wages), so such a course would need to take more than 4 weeks to break even (perhaps even more so for an in-house employee.)
A major reason we're not using KiCAD yet is most of our layout work is contracted out and it's hard to find KiCAD PCB engineers. For us it's too infrequent to justify hiring a full time engineer for PCBs, but a bit too specialised to have that skill in enough in-house engineers. But as the popularity of the tool grows I imagine this will be less of an issue.
Edit: typo