There are some more expensive options that don't have this 'feature'. Look for Zigbee or Z-Wave. Here's a comparison page:

https://www.security.org/home-security-systems/z-wave-vs-zig...

That being said, I do have some 'cloud' IoT devices too, most of which were purchased because they were:

A) Cheap

B) Made by large companies

C) that weren't Google

This makes me _reasonably_ comfortable that the device and service will likely run for a while. I have some WeMo plugs that work great, and I also bought some second-hand Amazon plugs for $5/pp at a thrift store.

I want to get some z-wave light switches and scene controllers and make the actual light outlets smart, rather than putting the intelligence into the bulbs themselves. Unless you're going to be using the RGB abilities, putting the intelligence into the disposable part doesn't make a bunch of sense to me.

To arrange it all, I use Home Assistant, which I don't love, but it's just the best of the open source solutions available.

The lightbulbs probably don't directly have Wi-Fi and communicate with the remote server, therefore probably support local protocols such as BLE, Z-Wave, Zigbee, therefore it's probably possible someone has reverse engineered them already (even if they don't have a local-only mode).

Take a look at projects such as Home Assistant, they enable a fully local experience.

Most smart lights these days are either wireless based on Zigbee (e.g. Philips Hue, IKEA's Tradfri) and standard profiles or, for expensive smart homes and offices, wired on KNX/EIB. With either of these, if the vendor goes bust, the only paperweight will be the gateway, but you can continue to use the appliances.

I have my lightbulb server rigged to toggle my lights whenever I flip a switch.