6% of 0 is 0, so you've picked an attractive time to make that argument. Your readers should just know that 6 months after starting their company, 6% of their company is 1-6 rock star team members. It could also be $1-6MM in a reasonable happy outcome.

I'm not trying to debate whether YC is a good deal; I'm objecting to the idea of spending more time and effort applying to YC than building an offering.

At least for me, those two were exactly the same thing. If you don't have a prototype, that should be one of the very first steps in your business. If you do, great - you have everything you need to apply.