If that was true, then why are there movies/series created solely for streaming providers?
It can't be there sole reason, and I sincerely doubt it's even true. Sure, the price of a single DVD would've covered the price of 1-2 months of streaming on Netflix, but people didn't buy a DVD each month. And if they did, they lent it to friends after.
Some bought the movie, others rented the movie, and others just waited for it to show up on their cable subscription where they paid 100-150/mo for. Not it is just 20/mo and whatever the box is.
It can't be there sole reason, and I sincerely doubt it's even true. Sure, the price of a single DVD would've covered the price of 1-2 months of streaming on Netflix, but people didn't buy a DVD each month. And if they did, they lent it to friends after.