back in the 1980s companies realized that by selling direct to consumer spare parts and giving manuals would increase their profits

in the 2000s apple realized that by disabling ANY repairability by anyone, even sometimes apple, they can increase their profits by forcing customers to just buy brand new full priced hardware with no other options.

In the 80s most electronics were not computer controlled, so changing a capacitor or mechanical part could not really be stopped. Today since software is such a critical aspect, they can deny repairs via software and anti-tampering tech.