It's an excellent time-frame that sounds imminent enough to draw interest (and funding), but is distant enough that you can delay the promised arrival a few times in the span of a career before retiring.

Fusion research lives and dies on this premise, ignoring the hard problems that require fundamental breakthroughs in areas such as materials science, in favor of touting arbitrary benchmarks that don't indicate real progress towards fusion as a source of power on the grid.

"Full self driving" is another example; your car won't be doing this, but companies will brag about limited roll-outs of niche cases in dry, flat, places that are easy to navigate.