I've recently set up Home Assistant again after a 5 year hiatus. All my old devices still work fine.

I primarily use zigbee, which is fully local and very reliable. Home Assistant supports a lot, including older hardware. I have a 2010 Philips LivingColors lamp (predecessor of the Hue) that talks early zigbee and still connects to a 2026 zigbee dongle + Home Assistant install.

I avoid any cloud dependency for the reason you give. Anything local, especially with open protocols and an active community, will probably work for a very long time. Likely the lifetime of the appliance.