Always has been.... This is part of the reason behind US Olympics push to change the culture of the Olympic team... They got most of the sailors on board with a team approach... cut the costs and increase the training and coaching time. Teams still had their international training partners... especially after selection and before the games.. This remains a key feature of the new plan just announced.
The cost of the boat always pales in comparison to campaign and training costs. Note... Countries get qualified for the Olympics by their representatives competing at the grade I events.... so... you could have one team trying to qualify the US.... or six teams trying to qualify the US... Once the US is in (based on performance)... then the US gets to pick their team... (now done by performance of the 6 teams at a couple of late ISAF grade I events.

You could always self fund your campaign and do your own thing outside of US Olympic and win the key selection events...