> using application performance monitoring software and analyzing query plans.

soo... tooling ? how is that different from using valgrind ? it's literally one click in my IDE to use it and it will show e.g. the time spent at each line of code directly in it.

> If you use Python and JS chances are you do some form of web development, where most performance issues have to do with I/O, and most of those I/O issues are caused by bad queries.

I don't know about this, what I know is that multiple times in my career I had people come at me with python software that was slow, and transliterating them almost line by line to C++ made them much, much, much faster.

Also I have all these apps on my system which apparently depend on python, none of them being a web app:

    Name            : 3dsconv
    Name            : anydesk-bin
    Name            : arandr
    Name            : asciidoc
    Name            : bind
    Name            : binwalk
    Name            : bpytop
    Name            : breezy
    Name            : carla
    Name            : ceph-libs
    Name            : cmake-format
    Name            : cppcheck
    Name            : cppman-git
    Name            : cython
    Name            : deluge
    Name            : deluge-gtk
    Name            : diffuse
    Name            : distcc
    Name            : fio
    Name            : fontforge
    Name            : fvwm
    Name            : fwupd
    Name            : gconf
    Name            : gcovr
    Name            : gdb
    Name            : gdb-common
    Name            : gdown
    Name            : glusterfs
    Name            : gnome-tweaks
    Name            : gobject-introspection
    Name            : gtk-doc
    Name            : i3-workspace-groups-git
    Name            : ibus
    Name            : inkscape
    Name            : iotop
    Name            : ipython
    Name            : itstool
    Name            : jack_mixer
    Name            : kajongg
    Name            : kig
    Name            : kitty
    Name            : kitty-shell-integration
    Name            : libffado
    Name            : libixion
    Name            : libopenshot
    Name            : libreoffice-fresh
    Name            : libsearpc
    Name            : libsigrokdecode
    Name            : lldb
    Name            : mallard-ducktype
    Name            : meld
    Name            : mercurial
    Name            : meson
    Name            : mono
    Name            : mypy
    Name            : namcap
    Name            : node-gyp
    Name            : nuitka
    Name            : openshot
    Name            : pahole
    Name            : paperwork
    Name            : pax-utils
    Name            : pcsclite
    Name            : perf
    Name            : ps_mem
    Name            : pyalpm
    Name            : pyside2
    Name            : qemu-tools
    Name            : reflector
    Name            : repo
    Name            : rubber
    Name            : samba
    Name            : scons
    Name            : seafile
    Name            : setconf
    Name            : smbclient
    Name            : smem
    Name            : solaar
    Name            : speech-dispatcher
    Name            : tellico
    Name            : thefuck
    Name            : thonny
    Name            : torbrowser-launcher
    Name            : udiskie
    Name            : virtualbox
    Name            : yelp-tools
    Name            : youtube-dl
    Name            : yt-dlp
    Name            : zim

incidentally, my day to day experience definitely does not classify any of the software I actually use in the "fast and enjoyable" category, except zim and tellico. Like, just launched a couple that I had forgotten about: solaar, a GUI for configuring logitech mice, and thonny, a minimalistic IDE for arduinos, etc. and they take actually observable time to start, on a 1k€ CPU, which I really find to be entirely ridiculous (and made me remember why I don't use them more).