I love this sort of internet comparison article: great for clicks and generating arguments, but not much real world use. Let's try a different example (using the original author's own numbers), a simple "holy trinity' f/2.8 zoom comparison. The A7Rii is now the lightest combo at 3798g and the K1 is the heaviest at 4672g, closely followed by the D800 (which, I feel, he was attempting to promote) at 4320g, the A99 at 4194g and the surprisingly featherweight 5D Mark IV at 3900g -a mere 102g heavier than the Sony!
The 'holy trinity' example that I gave, is weighted against Nikon (and Pentax) because it uses a 14-24 f/2.8 instead of the 16-35 f/2.8 of the other brands. Likewise, I think that the original author is referring to the Tamron-Pentax 15-30 f/2.8 in his comparison, which also biases against Pentax. If one includes an 85mm, it helps turn the tables against Canon because their's is f/1.2 instead of f/1.4 and in favour of the Pentax, if one accepts that the 77mm f/1.8 is a fair substitute! Sony loses out on the 50mm primes, because the FE 50mm f/1.4 GM is a modern high-performance design that is very sharp straight from wide open, whereas all the other brand's lenses he has chosen are far lighter, but soft as warm butter until the aperture is closed down a couple of stops -a fair comparison? How would it have looked if he had selected the Sigma 50mm f/1.4 Art instead (a far closer lens to the Sony resolution wise)?
This is also the case with his latest price based comparison: comparing old superannuated designs to new designs and including lenses that are not really exact equals in terms of market position and/or performance.
I am not trying to suggest that any brand is lighter/cheaper/better than any other, just point out that it is easy to skew these sorts of comparisons by including or excluding lenses (or other accessories). They are worthwhile exercises to do yourself, if considering changing system, as long as the lenses chosen are those YOU require and not some arbitrary list drawn up by someone else on the internet.