Two completely different animals there. The reason Blockbuster had to close up shop was because their overhead couldn't be reduced enough to compete with Netflix on price. I.E. When Netflix started, it was cheaper for most consumers to pay 8 bucks a month than rent movies at 3 dollars apiece from Blockbuster (not to mention the late fees). All they had to do was watch 3 movies a month for it to pay for itself.
Firstly, Redbox has eliminated the overhead of a brick and mortar store by using kiosks, so immediately they are much better positioned than Blockbuster ever was. Secondly, they have reduced the cost of the movies vs. Blockbuster and Netflix so it actually is a less expensive option. Lastly, they still offer new releases which you can only get with Netflix's DVD service (not streaming). Not everyone wants to wait a week to get a movie shipped to them.
Redbox will continue to be the preferred option for lower income households that maybe can't afford fast internet speeds, or the less tech-savvy consumer.