Yes, I think this seems reasonable, and I like the analogy with supply and demand, too. I think this is largely in line with what I write in the article. The problem with taking a course that isn’t created for your level is that lots of the supplied materials and activities will not be suitable, which creates an extra need to make up for that in your own time with your own resources, maybe without much help.

Language-wise, there’s also a problem in that what constitutes comprehensible input varies by level, so while reading/listening to a certain passage might be great for a certain level (the level the course is designed for), it might be a complete waste of time for someone at a lower level. The other issue, which I also mentioned, is that you really might miss some things the course assumes you already know, but that you actually don’t know (similar to what you said about C2 grammar). It isn’t impossible to compensate for this on your own, of course (I mean, taking a course is not necessary in the first place), but it does take extra time and requires some resourcefulness. At the end of the day, though, I feel that motivation is the key. If you really want to do it and can invest extra time and energy, it will usually be okay.

I think from a teacher’s point of view, you want to maximize supply and optimize demand. Forcing someone to do a course that’s beyond their level is bad. So is failing to provide materials that make it impossible to succeed.

But I think from the learner’s point of view, more demand is generally good as long as the learner can comfortably handle it. Intense goals create more motivation and focus, so the only downside is when the expectation is so high that you feel you can’t succeed and it backfires.

The only place I could see seeking out a more challenging environment being less effective for learning (assuming you’re below the threshold of excessive stress/burnout from studying) would be when choosing an advanced environment impacts the supply of learner materials. For instance, you don’t get proper instruction on tones because it is assumed you should know how to do it, instead you’re paying attention to C2 grammar points that come up infrequently.

Still, I tend to think setting a high, but believable, set of demand constraints on yourself for the environment is usually better, if only because we tend to underinvest effort in learning.

Just my two cents.

Hi! I’m not sure what you mean. It doesn’t say “lodge a submission ” anywhere in the article and it’s not obvious what you refer to. Could you please clarify?