One of Oyata's students has written that when a student asked about "bunkai" for a specific move, he might reply "What do you think?"
This is excellent teaching practice because it forces a student to begin looking at applications from the lens of their experience and needs. It's how you personalize bunkai.
But we should all recognize the distinct potential that historically, kata was handed down, perhaps without a whole lot of bunkai.
This is true. For the last 100 years, Shuri-te and Tomari-te kata were not taught with a lot of actual bunkai. Was this always the case? It seems like the further back you go in history, bunkai become more important.
Another thing to consider is that various karate kata have been so heavily modified throughout the years that they may have scrambled the bunkai they were supposed to teach.