They don't do it because the lawyers didn't see it as any different from their current streaming, that is, it would require a license. Since the license is the stumbling block for Netflix's sad lack of older streaming content, I'm not seeing how these shenanigans would help.
Form what I hear, the big problem for streaming license for older works isn't even the price negotiation, it's that the contractual rights are unclear for everyone involved in making the movie, when it comes to this new form of revenue.
Yes this could be an explanation for why there is no streaming of older content that was made before contracts were written to take streaming into account.
However, for more recently made movies, when everybody knew about streaming when the movies were made and the contracts were written, it doesn't explain why the studios release those movies as physical DVDs for Netflix to mail to people, but not as "virtual DVDs" that they could sell to Netflix for the same price, and that Netflix could then "check out" to people.
There certainly isn't some scheme by Netflix to offer DVDs to price-conscious users, since DVDs are so much more expensive to the end user than streaming, unless you only watch a couple of movies a week.
My wording was unclear; what I meant was that for the movies that Netflix has available on DVD (but not available on Netflix streaming), it's much more expensive to stream each of those movies if you buy/rent it from Google Play or iTunes, than it is if you just queue them up and have them mailed to you through Netflix. So that's possibly how the studios are price-targeting people: If you're willing to go through the inconvenience of queueing up movies, waiting for them in the mail, and then watching them on a clunky old 20th-century DVD, you can watch all those movies at a pretty cheap cost per movie. If you bought or rented those samne movies on iTunes it would cost much more.
"Religion is something left over from the infancy of our intelligence, it will fade away as we adopt reason and science as our guidelines." -- Bertrand Russell