If I were 21ish and had gotten this far, I absolutely would have made this choice, and it absolutely (for me) would have been the wrongest choice I could have made in that moment.
The credential matters, and is worth 10 fold the value of that checked box on interview applications. To the people whose opinion Simon likely cares about, it proves you can stick with something that's unpleasant long enough to see it through to completion. Completing college (or not, as it's something I haven't done) sticks with you in conversations, in social interactions, and in the minds of others.
If you ever want to do anything besides bootstrap your own startup all the way to product/market fit (not as easy as you possibly think right now), not finishing college will create a little nugget of, if not doubt, then "prove it now" mentality in the heads of the people whose opinions you care about (both professionally e.g. investors and personally e.g. friends).
If you're 20 or 21, your primary advantage is time. You do have the time to finish up college, and then do all of these things. You can do both, and pretending like you can't is just giving in to that underdeveloped prefrontal cortex.
Simon, I hope I'm wrong, but this is a mistake. You will regret this.