Why would we only get one chance to align a superintelligence?

If we failed to align a Superintelligence

on the first attempt, it might be powerful enough to ensure that its misaligned goals would not be hindered by any further attempts to align it. On the other hand, if it were still weaker than us, it could realize its weakness, and deceive us into thinking it was aligned, making further attempts to align it seem unnecessary. It could then turn on humanity when it was sure it could win in a confrontation.