Youtube started to break even in 2010. It means it was burning cash for the prior 5 years. That's the biggest obstacle, when it comes to a new kid on the block:

Youtube started to break even in 2010. It means it was burning cash for the prior 5 years. That's the biggest obstacle, when it comes to a new kid on the block: the entry price. You need a wallet that can't be emptied, at least for 5 years. Most probably for more, as you have to compete with an existing de-facto default service. And sure, Amazon may have a bottomless wallet... but would you want to burn its content for a project, that very well could fail spectacularly, with a very high chance?