I'm taking a random walk with Netflix to $1000 a share
In 5 to 10 years there will be over 2 billion broadband users. With a 25% market penetration Netflix will have 500 million subs with 50 billion in revenues. They already have over a 25% market penetration in the US and still growing fast. Netflix should have the same success where ever people like watching movies and their favorite TV shows.
There's only about 115M households in US. About 85M has internet. Less than half of that has really fast internet. Trim off really rich and really poor and non-computer literate households, leaves only about 50M. There's NO MORE USERS TO ADD, ONLY TO LOSE.
You are just proving garolou22's point to an extent. Using your statement, growth can come from the half that does not have really fast internet and the 30M that don't have internet. Also, of the 50M of household left after your computation, only half have Netflix (25M subscribers in US.)