This is the opinion of an amateur, but I think this is where "skillful effort" comes into play. A retreat like that will be less strenuous if you already have a daily meditation practice.
I wouldn't describe a weeklong meditation retreat as the "extreme" side of the Buddha's middle way. That would be more like starving yourself in asceticism. With the right practice/preparation (IE a few months of daily hour-long sits), I think a weeklong retreat would be beneficial and reasonable for most people.
Of course, getting to the point of a daily practice is pretty challenging itself, but not too much more than the average workout routine in my opinion.
Yeah, the point isn't that any given thing is hard but that throwing yourself into the practice that's really extreme for you might not be the best to start mindfulness.
In Qi Dao, our approach is based not on going beyond a person's comfort zone but extending their comfort zone.
Most people sit all day looking at a screen, then they spend a large part of their free time also sitting to watch TV series (generally ~40 minutes long) and films (~90 to 120 minutes long) so spending 1 hr sitting without a distraction hardly seems extreme in comparison, though I wouldn't call it particularly useful. Like physical exercise, you'll probably get more benefit from many, smaller but intense reps than large one off attempts.
I wouldn't describe a weeklong meditation retreat as the "extreme" side of the Buddha's middle way. That would be more like starving yourself in asceticism. With the right practice/preparation (IE a few months of daily hour-long sits), I think a weeklong retreat would be beneficial and reasonable for most people.
Of course, getting to the point of a daily practice is pretty challenging itself, but not too much more than the average workout routine in my opinion.