That is not true. Other automakers also have OTA updates, even e.g. Chevy trucks [0]. And some safety fixes can be mailed to customers to DIY. I did one on my Honda -- there was a typo in the owners manual on a safety critical statement. Honda mailed me a sticker and told me where to place it.

0: https://www.gm-trucks.com/gm-recall-brake-warning-light-fail...