Interesting points. My issue is with your contention that as a service company, you don't decide what goes into the software. This is where a web production/service agency can learn from the creative industry.

Such a service agency should position itself as an industry expert, one that clients turn to for solutions, not products. That is, if a client -- let's say, a chain of local gyms -- comes to you and needs a website built, it shouldn't be turnkey and you should expect to contribute your thinking to the end product, not just the code that creates that.

Not code monkeys. Inform and shape the final product, because you know more than your client. They need you for a reason. They don't know the best answer, you do. That's why they hired you.