Well, I agree partly. I'm also on a phone which doesn't receive security updates anymore. I don't know how risky that is. However, it seems clear that longer security updates are much more desirable than increased repairability. Most people won't need to repair their phone, apart from changing the battery after a few years. Especially not when it is a cheap phone anyway, where any repair cost is likely higher than a new phone would be. So a device with longer security updates seems still better than this increased repairability.