A few more thoughts.
Senior folks do not work more slowly than beginners. That is a misstatement and probably due to how I presented my original post (badly). If you don't believe me do the following test:
Take two 6th kyu's and have them do a specified technique for a certain amount of time. Then take 2 yudansha and repeat the process. The yudansha will absolutely complete more repetitions than the 6th kyu's assuming they are familiar with the technique. I predict it will be a minimum of 2 or 3 to 1.
The reason isn't speed of execution (although it would be a factor), it's economy of execution. Beginner's spend a lot of time messing things up, asking for help, talking to each other trying to figure things out, trying to center themselves, stumbling back up from a fall, catching their breath, whereas the more senior folks just work on the technique and because they need less help they can get in more reps. My practice, in the context of technique can be brought to a crawl if I happen to draw a beginner (please no lecture's on my spiritual impurity). I can spend 30 seconds throwing and 3 minutes explaining/showing.
Now that I've thought about it, I think the author's contention is that you put beginner's on the same work load as a more advanced person. However, doing the same work will take them longer, and it will be less accurate, hence, beginners would have to stay after class, work at home or take special training to get the necessary repetitions. Some of us do these things (or did) but the reality is that most won't because of perfectly valid reasons like they want to have a family-life or something.
Therefore, I believe the author is correct on speed then quality. Beginners don't have quality, with the occasional exception, but if you can't get a beginner past the initial phase of stumbling around for 20 seconds or whatever per technique you will never get them to the point where quality comes into play. They will never get the needed repetitions, unless, they work extra time. Perfect quality isn't, because nothing ever gets done. Plus, making mistakes counts for a lot in learning.
In regards to speed training. Anyone who has played competitive sports has had the experience of going up a level and having a "holy shit, these guys are fast, strong and way better" revelation. It can be a serious eye-opener. To me, this type of experience makes me seriously doubt the concept of always training slowly. I think the first time you are confronted with speed you will be tweaked by the speed if you've never seen it before. You need to work with something to learn it and speed is no different.
Finally, I think the author is talking about something that most of us don't want. I'm not prepared to give my life to a company and I don't think most people should give their life to Aikido either. There is something to be said for balance and enjoying a good sunset or sunrise.