And I'm only being slightly facetious.
The ability of modern hardware to download install an OS directly from firmware is a truly great and useful modern innovation, but it leaves a lot of unanswered questions: What if my network is bad? What if this used hardware is stolen? What if I don't have an account? What if Apple goes bankrupt?
USB/SD/DVD installers do not require network access nor any sort of account/purchase verification, and can be created (relatively) easily and officially from downloaded installers. I have bootable disk images for every OS X installer since OS X Mavericks and I highly recommend it.
I'll include a USB installer whenever I sell an old laptop. It costs me next to nothing and gives the buyer some reassurance that they're not buying a brick. And if I decide to hang on to a piece of hardware, I have some assurance that I'll be able to use it 10 years from now.
I almost always install after booting to a full OS X system on an external hard drive (so NTP syncs the time), either via a downloaded installer or after logging in to the wifi captive portal (since Internet Recovery won't do WPA Enterprise).
To answer your question: a non-technologist pays someone like you to fix it. Much like the way most people bring their cars to mechanics instead of spending hundreds of hours learning to fix the vehicles personally. This type of specialization is prerequisite to the large civilizations in which we live.
It's pure luck that I'd seen this type of issue before because I'm one of those mere civilians: my Windows machine at work loses BIOS settings on power down. I've seen that until the date is restored, DropBox and several other things don't work.