I'm guessing that ten-year plan is only roughly sketched out in the second half.
And yeah, I know they plan on sticking to three products and I'm sure they have sound reason to believe it is the financial sweet-spot in terms of maximizing profit while minimizing overhead. My preference for five products is not based on economics but what I'd like to see as a consumer and fan of D&D, and what I think would best strengthen and diversify the line. While I disagree with those who yearn for the output of 3E/4E days, clearly WotC has taken a reactive approach based on the glut-fallout of those prior editions. They went from excess to minimalism; my preference and recommendation is still minimalist (five products a year isn't that much, relatively speaking), but more "minimalist plus."
But again, I'm not questioning the soundness of their plan in terms of economics and the health of the brand. I'm speaking as a fan and consumer, and what I think would be ideal in terms of fleshing out the creative and entertainment possibilities of 5th edition.