Wow, that could possibly be the dumbest thing I have ever heard.
I consider Mission Control a dumbed down version of the Exposé-Spaces combo because it was a little on the more advanced side for the average consumer, I take it you fit into that category. So you probably never used it and saw why it was so beneficial to those who did make use of it.
I take it you never used spaces and expose together...
When used together, they were beautiful. Expose let you see all your windows in your current space, absolutely amazing. Spaces let you organize a virtual monitor that you could switch to in a fraction of a second to then start working with a variety of different apps at once. Say you have a lot of these virtual monitors set up because what you do demands a lot of applications open in a certain layout, especially with multiple monitors. This is where spaces shines. It is also where keeping spaces and expose separate shine as well. You can use expose inside of spaces to see all your windows you currently have open in every space! You can't do this with lion, you would have to go through each desktop individually, slowing people down significantly when looking for a specific window.
Spaces and expose helped keep the more advanced users organized and help them work much faster. But Steve is a minimalist, and I honestly can't see him having more than 3 windows open at once: safari, iCal, and mail. He's definitely not a power user in my opinion.