As a former transporter, I can give you some insight on to why they are more expensive. Those alleged Independents you are finding on u-ship are not Independents at all, rather they are the large vehicle transport companies that are trying to fill all their transporters going across the country. The biggest name on uShip would be Montway, and they love to schedule more than they can handle at discount rates, only to leave the shipper stuck with a vehicle they cannot move for weeks to months. the independent guys have to cover all of their costs, plus make at least some profit... And it costs around $1 per mile to operate commercially these days. With changes in regulations, even a guy driving a pickup pulling a trailer is subject to hours of service rules and can only drive 11 hours per day. This means he must charge more in order to survive. the independent is also paying $800 a month for liability insurance alone, plus however much their inland marine cargo rider costs. If the job takes a week, that load's share is $200.
Another thing to consider is the fact that most Independents you are finding will transport in an enclosed trailer, rather than on an open auto transport. This service also costs more to provide, as it uses more fuel and the equipment costs more.
For those saying to avoid brokers, that would be a mistake. You can actually strike a deal with a broker to ship it for a set dollar amount... And whatever amount they can get it shipped for less can be their profit. They will sell the load hardcore at a lower rate in order to make more money off of what you gave them. For example, last year my friend had a non-operational Land cruiser sent from Southeastern Ohio to me in Minnesota for $600... That was his cost to a broker. How much did the broker pay the transporter? The world may never know... but it's 825 miles door to door.