If the people who would use IPv6 don't like it and don't want it, if they think it's bad, then it's bad.
When forest rangers observe hikers repeatedly deviating from the official trail at certain spots, the ranger understands this to mean the trail is wrong, and he re-designs it to accommodate the hikers. The forest ranger is able to do this because he understands what the trail is for: it's for the hikers, and he empathizes with and adapts to the hiker's needs, not his own needs, not his ego, not his whims. Never does the forest ranger defend a bad trail. The forest ranger takes feedback without ego, and he is able to do so because he does not personally identify with the trail, he identifies with the needs of the hikers.
Engineers would do well to become more like the forest ranger. Many engineers seriously lack empathy for end-users, which results in the engineer creating inadequate products/services that don't meet the user's real needs. Even worse, when the product/service is criticized, when the engineer is given an opportunity to improve the product, the engineer instead blames the user, rather than himself, rather than adapt and recalibrate to the user's needs, he submits to his own ego, his own pride.
It's this lack of empathy and user-blame that yields poor results, results like IPv6.