I've definitely had realizations drinking alone. It's not a state you want to be in all the time, or even often, but it can be useful. It's sort of like a random jump in the mental search space to get out of local minima.
(Though perhaps I could train myself mentally to be able to enter these more loose states w/o alcohol, and that would be even better?)
Alcohol isn't special in this regard. There are many ways to shake oneself out of their standard mental cycles. There are lots of other drugs, and there are also plenty of non-drug techniques and experiences.
Guided meditation, hiking, hot yoga, intensely practicing music, watching challenging movies, skateboarding, scuba diving, and dance lessons come to mind.
(Though perhaps I could train myself mentally to be able to enter these more loose states w/o alcohol, and that would be even better?)