In cable/broadcast, the show was gone when it was cancelled. It wouldn't air anymore outside of re-runs (which rarely happen for cancelled series), and new content was designed to fill the space.
The whole freaking point of Netflix is that I can watch any item from their entire catalog at any time I'd like.
That includes all of those cancelled shows.
So as a user, I'm left in a really weird spot. I want the content that was cancelled, but I'm much less likely to watch a story based show if I know it was canned and will never be finished.
Basically - I'd argue strongly that Netflix is (intentionally or not) drastically undermining the long term value of their catalog by not allowing shows to conclude.
That's not to say they should fund a show forever, (it's still a business) but it does mean the intelligent thing to do would be to fund out some sort of conclusion or ending to those cancelled series.
A 2 season show with a 6 episode "conclusion" instead of a season 3 - That's something I would probably pick up and watch: I know it's a complete story and will have some sort of resolution (good or bad).
A 2 season show that was canned on a cliffhanger? Will NOT TOUCH. Fuck that. Doesn't matter how good it is, doesn't matter how much I like the genre - It's not a product, it's an unfinished waste of time.