Think about it from a sole proprietor viewpoint, if you have to claim an extra 10%, representing unpaid invoices, for example as taxable income it just cost you an additional 15.3% off the bat for self-employment tax as well as yoru margunal tax rate on this unrealized profit.
That 15.3% you quote is not really what you pay for SE tax, half of that is credited back on the 1040. 7.65% is a more realistic number. And partners also are self employed and pay that tax too.
I have rentals, I guess I am lucky, I have only had two deadbeats over the years, and I convinced one to pay the overdue amount before he vacated.
I just don't see the issue of writing off an invoice to bad debt as being a major issue at EOY - just me I guess.