…it's too costly.
It’s a false economy though. Maybe not 100% but usually if there is some balance between total coverage TDD and shipping early/often. Like buying something on credit with a large downpayment, you halved, at least, the total cost when the interest is paid off. You, in my view, take the right approach and I expect the hackers who work with you or inherit your code appreciate it. That said, “profit” is not a dirty word. Without profit, there is nothing to bank. Without savings banked, we’re back to toiling in the fields or on the seas and hoping the larder doesn’t turn before the spring.