The Newton had a short life, but garnered a loyal following, with active users more than 20 years after it was cancelled. The technology and ideas in the Newton eventually made their way into the iPhone and now live in billions of devices around the world. The later handwriting recognition system, Print Recognizer, made its way into OS X and could be used with a pen tablet. It was discontinued with macOS 10.15 in October, 2019.
There were retail stores dedicated to the Newton called Newton Source. They weren't actually run by Apple, but by a Newton enthusiast who wanted to improve on the computer store experience. The stores were more relaxed and had stations where you could use the Newton and talk to an assistant about them, very much like the experience of a modern Apple store. The original Newton Source in New York was only a block away from the current location of the Fifth Avenue Apple Store.
One of the most impactful decisions made for the Newton is probably in the device you use every day. In order to develop a low power CPU for the Newton, Apple joined with Acorn Computers and VLSI to form Advanced RISC Machines Ltd, better known as ARM. They developed the ARM6 architecture and the ARM610 CPU was used in all of the early Newtons. Today nearly every smartphone and many other embedded devices use ARM CPUs.
Like General Magic and other projects of the era that were commercial failures, Newton didn't survive but went on to influence things that most of us use every day.