The talent gap and roster construction issues are not mutually exclusive. There is undoubtedly a talent gap between the two teams. There is no one on the Celtics roster close to Giannis's level. And if you want to look at why this season's Bucks were better than last season's, most of that is due to Giannis, as he improved by 2.5 win shares alone. Win shares is not an ideal stat, but it can be descriptive. Kyrie is obviously second best on the floor, but there is a huge gap between them, IMO.
Horford is probably #3. He was clearly hurting a good chunk of the regular season, however, and the Bucks were probably a horrible matchup for him.
It's the next group where Milwaukee was deeper: Bledsoe, Lopez, Middleton, and Brogdon (obviously a non-factor this series) are all better (today) than Tatum, Brown, Morris, and Hayward. Smart's injury was big blow as well, as the Celtics had no-one to truly replace him, and he was clearly not himself either. I cannot imagine what it would be like to shoot with a sore oblique muscle.
There were also roster construction and matchup issues. Probably also chemistry issues, which were beyond Brad Stevens' ability to fix (and probably would have been beyond Phil Jackson's and Greg Popovich's as well).
Horford is probably #3. He was clearly hurting a good chunk of the regular season, however, and the Bucks were probably a horrible matchup for him.
It's the next group where Milwaukee was deeper: Bledsoe, Lopez, Middleton, and Brogdon (obviously a non-factor this series) are all better (today) than Tatum, Brown, Morris, and Hayward. Smart's injury was big blow as well, as the Celtics had no-one to truly replace him, and he was clearly not himself either. I cannot imagine what it would be like to shoot with a sore oblique muscle.
There were also roster construction and matchup issues. Probably also chemistry issues, which were beyond Brad Stevens' ability to fix (and probably would have been beyond Phil Jackson's and Greg Popovich's as well).