In my view, these are the top 5 problems faced by mobile video startups.
1) No ease of viewing video on small screens
2) The tech not worth enough to justify the data charges,subscriptions charges and premium content charges
3) Battery getting drained quickly by using mobile as entertainment device
4) Not enough bandwidth available on cellur networks for streaming and downloading video content
5) Mobile handsets supporting streaming video display are priced high.
And startups in this domain are positioned by what problem they are solving.