I think you miss the point. Photographers for over 150 years carried extremely heavy gear over long distances because they had to do so in order to get the performance advantages that such equipment offered. I cannot imagine anyone CHOOSING to carry 30-40 pounds of camera equipment if they could get the same or better performance out of camera equipment that weighs 10 pounds.
For me, this is not about the cost. It is frequently the case that the last 5-10% improvement in performance carries a very big price tag. I get that. I would pay (and have paid) for that. I own and carry medium format equipment with an 80 MP back because it offers capabilities that I cannot otherwise get. However, a Leica SL with a 24 MP sensor and that weighs what it weighs? I am at a loss to see what advantages it offers compared to a Sony A7RII (other than the EVF).
SL = 847g w/battery
A7rII = 625g w/battery + 2 spare batteries (2x42g) (if the SL is anything like the Q w/power management it'll take 3 sony batteries to = 1 Q/SL) for a total of = 709g and the annoyance of having batteries in your pockets.
That's not a lot of difference. AND yes the zoom is heavy/large/etc. but if the quality is good, and Sony had an SL adapter, how many people would buy it? Tons of people right now reach for R-zooms for their Sony. I even see adapters for medium format lenses.
BTW, I need to workout more anyway. I'm getting skinny.