(I've run many projects and have always been able to get some consumer feedback during development.)
"Release early, release often," would, for instance, likely be a poor philosophy for a team working on the computer vision systems used by armed autonomous military vehicles.
Could test early and test often be substituted successfully?
for all you know, we do... the U.S. has stopped measuring/publishing collateral damage for wars.
Games.
Complex games take a non-trivial amount of work to get them to where they're even remotely playable.