The trichromes contain the MOST thc/plant material. They're also on the outside of the plant. The alcohol sucks the THC out of the plant material, and reactions work fastest when they're hot. Drop some food coloring in ice water, then drop it in boiling water, and see which changes colors fastest.

When you cook it, you accelerate the process, and by grinding, you give the absolute most surface area to the alcohol, to further accelerate the process. It's Chemistry 101. If you stirred it while you were cooking it, it'd go super fast. Ever make tea? Throw a bunch of whole tea leaves in cold water and let it sit there. It might NEVER brew. Now, grind up your tea, put it in hot water, and stir the crap out of it! You'll have tea in two minutes!

The only part of the chemistry the pre-bake has anything to do with is converting THCa to THC, which when you smoke it, it heats up and converts. But when you ingest it the temperatures in your body DON'T. Pre-baking is a must for a potent batch.