For example things like form of your players, motivation of your team, etc... are just a few things that also play a part in the bigger picture
How are effort and form (GS I assume) not reflected in the ratings? More effort boosts some of the ratings, mainly defense, the same way home court does. Form boosts the way individual skills contribute to the team's ratings. So both are reflected.
There is a suspicion that the current team and individual ratings do not reflect correctly the GE, ie. some skills are undervalued in the ratings (SB being the obvious candidate here since its impact has been boosted) and others are overvalued. In particular shooting ratings by position are often mind boggling compared to the actual results. I have a specific suspicion that shooting ratings you see in the box score are not calculated properly when zone defenses are involved (the defenders in this case are not fixed) or perhaps even when defensive switches are used.