Harvest question for experienced growers...

General rule is that you harvest when 1/2-3/4 of the plant's bud is covered with amber trichomes.. my question is what would happen if you just let it keep going and didn't harvest? normally fruits and vegetables are the ripest and of the highest quality when it falls to the ground instead of picking it before it is ready. Would this not apply to cannabis as well if you did wait that extra time?

No, it would not, and I have only heard of one person say they waited until there was 50% amber.
If you read some threads on harvesting, you will not be able to find many people waiting that long. Most will pull at 20% or so, unless they specifically want the couchlock effect.

Once the trichome has turned amber, the THC starts to degrade, that's why it is important to harvest before the majority of the trichs have turned amber. If not it won't be as potent as it could have been. I like to harvest when about 10 - 15% are amber and the majority of the pistils have turned dark, but you can't always go by pistils.

TBH I rarely ever let mine reach even 10% amber, I prefer more of a high than a stone. Amber trichomes represent the degradation of the trichome it self, and there for the degradation of the cannabinoids within (i.e THC to CBN). Higher concentrations of CBN tend to make a user feel drowsy and shit, so try and avoid.

In simple terms, the longer you leaves cannabis after it's reached peak potency, the potency will decline. It is a flower, not a fruit or vegetable.

Mostly amber=shitty headache