People often change their minds, and are inspired to see other films when browsing. Having said that, The biggest advantage the online destinations have vs a brick and motar physical store is volume, and you can't compete with that.
The latest movies - sure you can get that. I think the real question for financial success is to offer a "flavor" or style, that isn't generated by an endless catalog, because you just have to get the people who are there, rent what you have, and be happy about it. They have to see what you have, and think "Hey that looks cool/good! I want to watch that." Even if it's an older movie.
I think people who are leaving a store don't know what they want, and can't make up their minds, or aren't inspired by anything they've seen. I think what you're aiming for is a niche destination. It can never compete on a sheer volume of scale with Netflix, or other services, but it will need to offer something that captures, and rewards a certain group of people. Somewhat like Starbucks vs the local coffee shop.