Yeah, that's the second exception in the article. RCLV - a real customer lifetime value to calculate your other costs against. But doing internet stuff since 1998 and startups since 2008 I have yet to encounter a LTV that is not full of.... wishfull thinking.
I second this. I've worked for a variety of early and mid-stage startups in my career, and to varying degrees, all of them had a non-trivial amount of hand-waving in calculating their LTV.
To stay longterm successful R > C!