This is a good time to bring up the fact there was never an industry-wide standardization effort for laptops. A standard form-factor means components would be re-usable between upgrades: the laptop case, power supply, monitor, keyboard, touchpad could all be re-used without any additional effort. This improves repairability, is much better for the environment, and means higher-end components can be selected with the…
Manufacturers probably don’t want to standardize on the remaining motherboard/graphics/chassis/cooling because a laptop isn’t like an atx computer where you get modularity at the expense of wasted space. A laptop is basically a 3D puzzle with thermal components. Few consumers would buy a laptop with even a little wasted volume or weight, even if it meant better serviceability and upgradeability. Same with phones. We aren’t going to see modular phones beyond the concept stage either.