Lack of memory effect has more to do with how we use our batteries than the technology advances of the battery itself, although there are a few. Memory really only happens when you discharge a battery to the exact same point with the same discharge rate and then charge it exactly the same amount each time on a regular schedule. For example, the aerospace industry would have issues with NiCd batteries in satellites. The satellite would drain the battery exactly the same amount until it came around in orbit into the sun to be charged. The battery would be charged/discharged exactly the same amount because of the consistency of the orbit. That's when you'd have memory issues. We never use our batteries in applications that have/require this precision and consistency.