I'm simply designing what would be sensical based on what it would be like if the RAW trade scene existed. I think I figured it out. Not quite like the OTU presents as financial institutions aren't likely to finance much of what is supposedly flying around "trading". There will lots of modified for additional cargo space old Scout ships and subsidized vessels that have been sold off when old, etc.
A lot of that is reasonable for frontier and not much population areas. But I would say the banking deal is propped up BY the Cr1000 and Passage standards, precisely so they make bank AND having plenty of Free Traders and such running about doing small packet/passage trade.
I figure a few things are happening outside of the expressed trade rules to help with that.
Part of the mortgage is being used by the banks to buy insurance against the loss of the ship per se, or more accurately the means by which the money loaned is to be paid.
The insurance goes strictly to the bank and assumes the ship owner/debtor is cleared of any wrongdoing or negligence, and is in fact lost.
The debtor is cleared of all requirement to pay/service the debt, but also gets no compensation for the loss of the payments they have made. Any such arrangement will require additional insurance they let out.
Another bulwark against loss by the bank is the repo trade. Being so tardy on payments as to trigger repossession proceedings means there is a great deal of interest, pardon the pun, in regaining the collateral of the ship itself.
Regaining the ship in reasonable shape means it can be repaired, re-certified and put back onto a loan at a reduced 'sales' price, or sold at auction. It may even work out to be somewhat profitable, a greater sum realized between down payment and payments made plus the sale of the ship, and the bank has it's principal back to loan again.
The insurer bond companies may send their own repo teams out to make sure they don't have to pay on a claim of loss by the bank. Or in your universe, it may be declared piracy and therefore naval/patrol vessels or privateers that gain a salvage/prize reward for a percentage of salvage auction.
The repo trade should justify a newer set of used ships available at lower costs.