Safari in macOS ignore no children processes memory info

[MazzMat]

In macOS tracking Safari main pid seems not to take care of children processes memory info

macOS BigSur 11.5.1)
Safari 14.1.2
Python 3.7.3

EXAMPLE taken with this command:
sudo psrecord 39720 --log process.txt --include-children --interval 2
while opening a lot of new tabs

Elapsed time CPU (%) Real (MB) Virtual (MB)

   0.000        0.000      230.277     6517.668
   2.017        5.400      230.344     6518.219
   4.044       15.000      230.465     6518.336
   6.061       42.900      230.922     6519.691
   8.090       55.600      231.098     6521.992
  10.105       40.700      231.828     6521.992
  12.137       17.000      231.730     6520.469
  14.161       81.300      232.609     6521.070
  16.189       61.600      232.980     6521.328
  18.221       31.200      231.961     6520.262