It's college football, you turnover about a quarter of your roster every year. You can become good overnight, plenty of teams have done it. We are only looking for decent right now. Part of being decent is playing correctly. If the other team is bigger, faster, stronger then there isn't a lot you can do in the bigger picture. You can only hope to pick them off on a bad day or by playing well.
Well, the other teams aren't bigger, faster, stronger and we aren't playing correctly. In fact, we are relying almost exclusively on the other team making huge mistakes and the individual efforts of a few guys. This is not a team that plays cohesively. It's also not a team playing the way winning teams win. Played perfectly that defensive scheme only loses by fewer points. You can't let guys run free like they were doing. You need your LB's to get to the ball before the runner picks up 4-5 yards and you need them to stop him before he picks up 8. You need to actually cover guys in a zone defense. You need to get the ball to your WR in a spot where it can be caught.
The rain clearly was affecting Bryant's ability to grip and throw but defense rendered that game unwinnable.