In summary, as I read the article, Apple's ARM puts a lot more defenses in place and enables app developers to add their own, such as in app encryption which makes existing malware exploit techniques less likely, but that is at the expense of making existing exploit detection less effective.
That sounds good to me! 👌 Exploit developers earn their keep by thinking out of the box and continually coming up with new ways to penetrate existing hardware and software systems. If the Systems Security community has a prayer of keeping up with their adversaries they too need to think out of the box and continually come up with new ways to detect exploits. Personally I would hope they see Apple's ARM security as a challenge to be met rather than a hinderance to their work. If not, then we need to throw in the towel because the security battle has already been lost. I view the author's concern not as a criticism rather a scouting report from the security frontier and a warning to his compatriots that the battle is not over, but new tactics are needed. But for now at least, Apple may be a bit ahead, but it is unlikely that will last long.