I don't understand this too. There are many 250er and sone challenger which habe live streams from the first round on. But the two biggest tournaments after the Grand Slams haven't.
Probably the ATP (which produces the Masters 1000 series) thinks that these 1st round matches are not attractive for the TV stations or so... or it's to expensive for them.
But it really sucks...
please don't give the seeds between 17 and 32 byes (112 draw would it be then, no?) in the 1st rounds, it would make them way more attractive. Or just remove these f*cking 96 draws and make it 64. I'd be for the latter. These two tournaments are often very boring during the 1st and 2nd round. The tournament "really starts" for me with the round of last 32, then it gets interesting.