Every team has their own criteria and their own definitions, but I have to say that this is the level I attribute to an intermediate developer. Similar to the original article - If I leave this developer alone to do their work, they will get it done. Honestly, I want every single developer on my team to be at this level. It takes time to get there, but not an inordinate amount of time in my experience. Somewhere between 2-7 years, anyway. If someone doesn't get there in 7 years, then I see it as a pretty big problem.
If you think that my estimate is not totally out of whack, that leaves all people with a 4 year degree hitting this level before they are 30 (assuming they start out in this field).
If this is "senior", in what way do you expect your employees to improve in the next 35 years of their career (assuming they retire at 65)? And what title would that have?