This is really taking the whole "I could build Dropbox in a weekend" style comments to a new level.

It does if you have no idea how it works.

Erlang fault-tolerance FTW! ;-)

Almost; you need maintenance and monitoring but that doesn't take anywhere near 100k people - assuming they even use their own headcount for this instead of just outsourcing maintenance to their equipment vendor.

Big Tech companies operate much more complex systems (for starters, they actually build greenfield stuff instead of buying ready-made equipment from a vendor and plugging it in) and have way less headcount.