Hidden .DS_Store files not appearing in Finder despite enabling display of hidden files

.DS_Store are special metadata files created automatically by Finder.app.

Finder.app is programmed to keep .DS_Store files hidden even when using the Command + Shift + . keyboard shortcut to toggle display of hidden files.

Since they are not user managed files and are intended to be used internally by Finder, they are not treated like other hidden files and kept hidden despite using the said shortcut.

The aforementioned is w.r.t. macOS Mojave 10.14.4.

I'm not sure what command the Cmd+Shft+. shortcut invokes, but to truly show hidden files (on 10.9.* through 10.13.*, as of today), use terminal to execute:

defaults write com.apple.finder AppleShowAllFiles TRUE; killall Finder

For 10.6.* through 10.8.*, use (note the capitalization difference in the first instance of Finder):

defaults write com.apple.Finder AppleShowAllFiles TRUE; killall Finder

Source: http://osxdaily.com/2009/02/25/show-hidden-files-in-os-x/
(I'm definitely not a fan of osxdaily.com, but it works.

Additionally, to check on your current value, use

defaults read com.apple.finder AppleShowAllFiles

... and for simple usage of the defaults command, just enter defaults with no arguments.

I verified that the value on this system is set to TRUE and I can see all the .DS_Store files as seen below... (using 10.11.6)