Why are manufacturers of hardware wallets trusted either?

I understand that its always been advised to source a hardware wallet directly from the manufacturer, never from amazon or a reseller, and ive obeyed those recommendations.

But why is the manufacturer to be trusted either?

Say a hardware wallet from Trezor, who seem to have been top standard for many years. Even their old models appear to have used entropy of multi sources, but is the next attack going to shock everyone and be one of these companies directly sourced hardware.

Should we be switching back to an old linux laptop with no connection to the internet and perhaps using just core software for wallet creation? At least that software has hopefully been throughly audited by the larger bitcoin community?