Speaking of food related ideas, when can a grocery store let me just pick up things, and walk out the door? Why can't I walk in a grocery store, swipe my credit

Speaking of food related ideas, when can a grocery store let me just pick up things, and walk out the door? Why can't I walk in a grocery store, swipe my credit card, then just fill up bags, and walk out? Or pause for a second at the door as it verifies my CC is good for that amount, then allow me to walk out. It's such a waste of time to get groceries, wait in line, unload them at the cashier, scan them all, pay for them, reload them again. Couple of ideas... 1. Some type of RFID tags built into all items, so the checkout can read all the prices when you step through the scanner. 2. You order everything online at home. When you get to the store, you swipe your CC, and your order is automatically picked in the back warehouse, and comes out out within a minute. Downside, this wouldn't work for certain produce, where you want to pick the bananas that look the best, or the green onions only if they're up to your freshness standard. However, it could be combined, so you order 95% of your groceries ahead of time, then just pickup the few extras and add them to your order waiting at checkout. This would mean 95% less time picking out items, faster checkout times since 95% of your items don't need to be scanned, or bagged.