It depends on your market. If you're aiming for people at home in Seoul, yeah that's probably alright. Their connection should be great and stable. If you're aiming at people transiting in Mumbai and watching stuff on their phone in the local train, 720p won't do.
I was referring to (small and medium sized) personal blogs and websites (like the one in this post), i.e. not a digital commodity on a market. If you're out there to make money I realize you have to be more fancy with what you put out there.
Let's be more concrete. How many people will you lose today from your audience if you just offer 720p? Hard numbers please!