How far back do you want to go with that? I remember assembling computers out of video boards, motherboards, etc.... but there are some people that remember soldering chips together... or transistors... or tubes... or relays. The trend towards higher levels of integration in computing extends back to the 50's (or maybe 40's).

> Computing was more fun

Fun is where you choose to find it. Modern machines are so good that they can be fun too.

A trend driven by tighter hardware integration and "security" (sadly it is as much about who is actually in control as any security for the end user).