It's functional - yes, intuitive - maybe, but optimized is highly debatable.

The answer to maintaining a highly functional and stable OS is piles and piles of backwards compatibility misery on the devs.

You want Windows 9? Sorry, some code checks the string for Windows 9 to determine if the OS is Windows 95 or 98.

Millions of total computer noobs hit the ground running with Windows 95. It was a great achievement in software design.

He was talking about user interface not app compatibility