You’re making a lot of assumptions that only hold when they are secure systems. If there were a ton of security holes, neither would have the share they have now. They built their empires based on being a top general choice. Security has always been important to early adopters in particular and general users care as much as it affects them. Sure, they could introduce holes now and get away with it, but it would hurt them relative to the other, so security is still a concern for both OS’s.
None of that really has to do with the quoted text though, so I’m not sure what you’re disagreeing with. While not every company cares as much about security, there’s still plenty of work there, particularly in big transactions handled by banks, airlines, and more. The second sentence is pretty much a truism. The constant arms race between security and hackers will pretty much never end simply because of its nature. With data becoming one of the more valuable things in the current tech world, protecting it isn’t going to stop being important. Some companies can fall completely apart based on one big data breach. I’d say that’s incredibly strong incentive.