Seems like cheap auto off timers and simple motion detector lights would solve all those problems with 1970s technology and no network connections at all.
Motion detectors generally makes things less convenient, not more. Now I have to wave my arms around regularly. No thanks. I'll take the network connections any day - the user experience is far superior before getting into that this was just one example.
If you always leave and come back at same time, sure. If you dont, fiddling with timer to turn on power just because you got off work early would be a bit of a bother.
I highly doubt the ability to turn my lights off over a network will destroy the world.
And if you're concerned about internet access, there are plenty of hubs for smart projects that don't need internet access. Some don't even need or have wifi capability, but can be wired physically into a dmz with an open source home automation system like Home Assistant. There are USB dongles with Zigbee support as well that you plug straight into your open source based home automation box if you want.
That said: Most people just don't care most of the time, because for most peoples use the worst possible consequence is being slightly inconvenienced.
E.g. should my Lightwave RF gateway get bricked, the worst case scenario is that my Lightwave switches revert to being dumb switches and I'll be slightly annoyed I won't be able to voice control them.
Hardly world-destroying stuff.
What's slightly different here is that this is a new move for Hue (it's not for any number of other smart home providers people happily sign up for online services from), and so some subset of their customers will feel compelled to switch zigbee bridges and incur a cost. (But if you're price sensitive, why the hell are you using Hue in the first place?)
No, because I don't want my termostat to switch off, my clocks to reset, my home server to go down every time I go to the shops or have a meeting. And no, I'm not about to rewire the house to provide isolated circuits just for the things I don't want to switch off, when I could instead just replace a few light switches and plug in a few smart plugs.
I can assure you pretty much nobody goes to their fuse board and trips the main switch even when going on holiday, much less during their day to day life. Many of the people who don't do that still tend to turn off as much as possible when leaving the house.
It's not critically important, but the many individually small conveniences add up.