This may be a regional thing, or your friends skew towards non-normal. Almost everyone I know understands tethering, and is comfortable using it. I'm in Sydney, Australia, where free wifi hotspots are perhaps less common than your part of the world, the people I know are not (to my knowledge) abnormal, mobile data services are typically fast, but costs are also quite high.

It is a source of some frustration that devices connected to a tether will assume 'wifi therefore unmetered' and do all the non-time-critical stuff (such as application updates) that you'd really rather that they do on a genuinely unmetered wifi access point (eg. home cable or ADSL) later on.

Same here. I've talked with multiple untechnical people who have managed to tether their iPads to their iPhones without problems.

Plug in your phone to your laptop and it works, no need to fiddle with wifi.

You're replying to someone talking about tethering their tablet onto their phone by wifi access point ... and suggesting they plug their phone into their computer.

I have experimented - in both Debian and Windows 7 - using plugged-in / USB connectivity, but a) it's a bit spotty, b) it means I need a cable connection and that's often not ideal when on the go, c) it doesn't (as noted) work with tablets, and d) it doesn't solve the underlying issue of slave devices thinking they have non-mobile(3g,4g,lte,etc) network connectivity and sucking down lots of data.

If you cripple your software just because the average user isn't a power user, there will be no way for average users to become power users because there's no advantage to doing so.

Reliance=revenues

Able=self-reliance

<Monop/Oligop> Corporation, Inc is not remotely interested in the latter.

I'd posit that the majority of road warrior types know how to tether.

In my extensive work travels over the last decade I was surprised how many do not for reasons other than ignorance. In the US, the ISPs explicitly & implicitly denying tethering usage made for a very confusing time late 2000's/early 2010's. When VZW(and the other big 3, I presume) gobbled up the smaller competitors they banned tethering, then charged extra for it(after or until the toothless FCC intervention?). Masking user agents, creating on-site APs out of old linux laptops+Mobile Data USB and the flaky USB data port enabled routers worked around these restrictions well enough. Have these policies been changed by the providers to where it is simple for average users w/out system tweaks or custom ROM features?