"...when the 'smart' things replace the 'norma' things so you no longer have a choice, what do you do?"
Well the first thing you do, is wait 'till that happens. And it won't happen for a long, long time - assuming that it ever happens at all, which it might not.
What I find more likely is that manufacturers will eventually made legally liable for the security of their devices, and be forced to guarantee a device's initial security and provide for ongoing security maintenance. Expect that to greatly diminish the hare-brained "IoT" enthusiasm now on display - and guarantee the continued availability of "non-IoT" appliances.