I'm sure the actual figures will depend significantly on what options are used to build up the kit. the title doesn't exactly suggest the budget options where being considered!
Even sticking with the choices they've made Mirrorless (Sony A) comes out lightest.
Actually, if you watched/listened to the video you would find out that they did use budget options.
From the bit of the video I have seen (I got bored with it) He claimed to selected the best in each range except for the odd ones which were too big/expensive. Nikons latest 70-200 being an example where the older model was considerably cheaper & 'good enough'. If it's not PURELY the best/most expensive it shows bias in selecting which ones to drop down on.
The choice of a 5 lens kit seemed excessive top me especially when the 85mm 1.4 was an option not present for Canon or Pentax, and alternatives had to be substituted.
The cheapest FF kit appeared to be as a separate video done earlier. In any event a simple comparison of DSLR vs Mirrorless doesn't work if based on
mostly the most expensive kit.