The problem is that planetary systems have now been discovered that violate all of these predictions. Not only has a few planets been found with highly elongated orbits but many Jupiter size planets have been found orbiting extremely close to their star. Even worst a quarter of these hot Jupiters have been found that orbit opposite the direction of their star’s rotation.
The response to these repeated failed predictions has been to repeatedly patched the theory to account for the discrepancy so that the planets start where they are suppose and moved to the observed position. The latest example of this is the of computer modeling to find a way for an unseen distant planetary body flip Jupiter size planets into reverse orbits.
The end result of all of this modification is that the nebula theory of planetary formation has been rendered unfalsifiable by the repeated patching. Being falsifiable is an important aspect of Science. The point is that instead of the usual scientific practice of abandoning theories that blow prediction after prediction, this one keeps being modified to explain away the prediction failures. It is getting to the point that no mater how contrary to the theory some new model will be created to get a planet from where the theory says it should be to where it is actually observed. The point is that by explaining away failed predictions makes a theory unfalsifiable and effectively unscientific.
Ultimately the reason for this is that the nebula theory of planetary formation the only naturalistic model left with that the only alternative explanation left being divine creation. The point is that the scientific establishment must protect this model at all costs and no discovery will be allowed bring it down.