: 2. "Easier on your body" ?
: Yes, since it produces less resistance, our muscles do not work as hard.
: What about the frequency and total stroke count? It takes more 'greenland
: strokes' to move the boat a given distance.
: Our bodies do have a hard lifetime limit how many times we can bend our knees
: or swing our arms. Greenland paddle uses up that limit faster.

Not actually true, in no one's body "owner manual" its written that you have available so many thousands swings and so many million knee bends. Our body structures can adapt overtime, on a small individual scale thats what training is for, to let the body strengthen the potentially stressed parts so that they can take more work.
Overuse its an abuse of the body in "quality" of effort not in quantity, and thats what has to be avoided, you can carry a ton of sand a kg at a time and your body is ok with it, or you can ruin yourself putting all your effort in even just trying to lift the whole ton in one shot.

: Muscles are very adaptable and resistant to wear and tear. The tendons and
: joins are a different story.
: Greenland paddles go easy on the 'sturdy' subsystem (muscles) and hard on the
: vulnerable ones.

Thats actually incorrect, the muscles are attached to the bones by the tendons, what one takes the other takes too, a small number of repetitions of a great effort can cause tendons problems too.
Joints can also adapt to a certain extent, beyond that taking care of the joints can maintein them in order for long time. A proper paddling technique (with whatever kind of blade you prefer) teaches how to not put strain on the wrong parts of your body.

: If large-blade paddle feels too hard to pull through the water, there is
: simple solution: Apply less force.
: You will be easier on your body yet still efficiently move the boat, not stir
: the water.

: So why there are armies of die-hard greenland paddle users and proponents?
: Well, greenland paddle has it's (albeit narrow) niche: when the wind really
: blows hard, or there are no materials to make larger blade,
: greenland paddle will do.

: Still, the large blade "euro" (why it is called this) paddle
: evolved for a good reason - most of the time and for most people it is
: superior to greenland stick.

If you look at the paddles used in different part of the world in different ages you will find that wide paddles evolved right beside narrow ones, and one was preferred to the other depending on the particular situation these populations were in. In a marsh for example your supergreenland paddle, the stick, is more useful than a gp or an euro, in whitewater a long narrow paddle wouldnt give you enough push to control, at sea you need something that lets you paddle the distance. Some population were living in areas where by necessity they developed and use both shorter and wider blades and a long and narrow ones, each one in different situations.

And talking about evolution the kind of blade shape of a greenland paddle is not exclusive of inuits, was developed and used at sea by others (that did have available the material to build wider blades) that had no clue about the artic populations. And in any town with an harbor you will still see that.