Exactly. If a single company could not be granted an artificial monopoly over upgrading and repairing a system due to "intellectual property" laws, no company could decide when a device has become EOL. If anyone could maintain a system, anyone would maintain a system.
With some caveats. I've run used chromebooks as my only laptop for about 5 or 6 years now. You have to undo write protection (usually a screw on the motherboard) and flash an aftermarket firmware.
