I'll confess that didn't watch this entire interview, but what I did hear can be summed up in this quote(@ 3:45): You only feel motivated to do the things that are easy.
And for me that describes a difference in how I feel about software development than I did about practicing law or any of the other career paths I tried. In software, I found something that I enjoy even when it's difficult.
What I do with that information, I don't really know. On the one hand, I feel like I hit the jackpot. I get paid to make stuff on computers work. I did this before for free, but now I get to do it using better tools where the possibilities are incredibly vast and the money is pretty good.
I don't really know what to say to people who haven't found what they're looking for yet. I went through three careers before I found one I really enjoyed, but I don't know that I should recommend that path, right? There's an interesting Freakonomics podcast episode about minor baseball players who, by every conceivable metric, should give up on their dreams. http://freakonomics.com/podcast/new-freakonomics-radio-podca... But that's a really hard thing to say to someone.
At the end of the day, I agree with your point that you don't need motivation, but geez, if you find it, it sure is pretty great. The question is, what are we willing to give up in order to find it? It's not an easy question.
Quit thinking you need to have motivation!