Ironically, of the laptop schematics I have collected, none of them seem to have been created in Altium either; they appear to be a mix of Cadence and Mentor, which are even more expensive than Altium.
...and their circuitry is extremely similar, being based on the Intel/AMD reference schematics. Anyone who has done computer repair and troubleshooting and seen the various OEM schematics will realise this; they each have their own style, but there are otherwise few differences.
* Requires commercial EDA package that will cost you more than a laptop