Earlier quoted context omitted.
> I live in the USA, this year we both sold our previous home and purchased our new home without the use of signage, open houses, tours, realtors, etc. We found the house we bought and found the buyers of our old house through our network of friends. We filled out all the paperwork from forms we printed off online. Surely you left a massive amount of money on the table then, right?
In what way? We sat down and decided how much we wanted for our house and told the potential buyers how much. They thought about it for a day and then told us they would give us that much money for the house. Maybe we could have made more on the open market, but we were happy and they were happy.
That's my point. You could potentially have made a lot more money on the open market. Especially if the buyers didn't even try to negotiate. That usually means they would pay more (let alone what other buyers might pay).
The value of your house is what people are willing to pay for it, not what you think it's worth or what you want for it.