Having spent the last 8 years of my life building a streaming film company that has from day one streamed globally and dealt with this patchwork of rights issue, I can tell you one reason:
Other than China and India, no other market is as big or insular as the US. In Europe people travel across borders and speak multiple languages all the time, and yet it's like pulling teeth to put together multiple regional subtitle rights for use in a country where it is not the native language. For someone to subscribe to Netflix and be able to use it in multiple countries with the subtitles of their choice consistently available is a huge benefit to a huge number of affluent users. This is something which the existing film industry is incapable of doing structurally, and therefore is a huge advantage that can only be replicated by the biggest producers (ie. major studios). And those big companies do not have product development and UX in their DNA, so they will struggle to compete with Netflix in this regard (to date only HBO shows promise). But meanwhile the Netflix experience will be so much better that they will undermine the foundations of industry.
I'm reminded of how in 2007 no corporate IT department would allow employees to use iPhones, and even though Apple never explicitly addressed the enterprise market, and Microsoft bent over backwards to give corporate buyers what they wanted, at the end of the day companies which didn't allow their employees to use their iPhones for work suffered a competitive disadvantage.