He had already seen exponential growth in storage capacity and could easily extrapolate from that. Moore's law was coined in the '60s, after all. This wasn't a

He had already seen exponential growth in storage capacity and could easily extrapolate from that. Moore's law was coined in the '60s, after all. This wasn't a lack of foresight, this was being prudent. If I can't come close to testing an upper limit, it's correct to acknowledge it may degrade in a way I haven't anticipated. Especially since he was writing a GUI which should generally avoid handing users footguns, and which can be updated over time.