From rather ancient memory, the high-end Ettus stuff is much, much more expensive than its BOM cost. You're paying for a well-designed and well-tested product

From rather ancient memory, the high-end Ettus stuff is much, much more expensive than its BOM cost. You're paying for a well-designed and well-tested product with excellent RF performance and a good ecosystem. You buy it and it works. You could design your own board(s) with the same parts, and you could build it for much less money. But you'd need to know what you're doing, and the design stage would be expensive.