What happened to SSL3/TLS1.0/TLS1.1 end-of-life will also happen to Wifi protocols: WEP-only devices are already out, WPA1-only devices will be next to lose access to a properly secured wifi network.
The longevity of the dumb parts in kitchen appliances exceeds that of the smart boxes in them. The manufacturer cannot slap a 20-years maintenance-budget onto the sticker price and I also don't see customers paying for a yearly maintenance subscription for 20 years (for each connected appliance). It will take a decade until people have learned that the shiny new iOT features are a burden in the long run. Maybe iOT maintenance longevity will get sorted out sometimes. Until then I refuse to buy such crap.