This is an interesting take. I'll have to think about it.
My initial take is to disagree in that 99% of assignments do not involve valuation of the existing mortgage, which frequently do not transfer with a prospective sale anyways. Don't want to put words in your mouth, but I'm guessing that you are thinking more on the accounts receivable/ accounts payable standpoint? If so, that is certainly an issue that could effect the sale, as is inventory that is typically valued separately in the sales contract. But as an example, I just completed an assignment of a +/- 50-year-old c-store in the past month or so in a town of 2,000. Didn't have indoor restrooms and functional obsolescence was certainly identified, but the actual performance was quite strong and I identified a high percentage of intangible assets. Would A/R and/ or A/P plus perhaps all other long and short-term debt payments really diminish BV to a nominal number? I remember the financial statements pretty clearly, and this specific case, there would not be. But from a positive leveraging standpoint, average long-term debt rates and average EBITDA cap rates support taking out pretty substantial debt, which would not negate BV IMO.