NBA

There is a lot of speculation around that being the case, as well as Lonzo not being taught proper lifting form and starting to workout at a young age. Another factor was potentially the BBB shoes, which were absolute trash quality wise, and Lonzo even stated he would have to swap out pairs at half time or sometimes after 1 quarter of play.

Another known factor for modern youth athletes is that with the rise of AAU and scouting happening earlier and earlier, kids play only one sport and overwork the same muscles and tendons, whereas a kid playing different sports year round is getting a more varied and balanced workout. I read an article (i think from the Athletic?) that estimated your average year round AAU player that enters the NBA will have more mileage on their body than Michael Jordan had during his full career, considering the high volume of games they play in tournaments, and most kids being on multiple teams.

If his dad had him playing basketball only year round and you account for all the other things I mentioned it makes sense that his knees were overworked, were not being properly cushioned, and were not able to handle the stress of NBA play in the long term.