I have never needed calculus since leaving university, nearly 40 year ago. If you're not in hard engineering, you probably won't (and if you are, you'll get to use all the computer assisting tools you want).
If you don't know math, you often won't be able to even realize when math is needed.
There's a Steve Yegge quote about this:
> You'll gradually realize that your math deficiencies aren't just something that you might need to beef up on if you ever "need to"; you'll see that virtually every problem space has a mathematical modeling component that you were blissfully unaware of until Done, and Gets Things Smart gal points it out to you and says, "There's an infinitely smarter approach, which by the way I implemented over the weekend." You stare slack-jawed for a little while, and then she says: "Here's a ball. Why don't you go bounce it?"
You're right that most people don't need to know calculus in their lives, but to my knowledge calculus also isn't generally required to get through college/university for most people, so it's fair to assume that the people in the course are there because they need or want to learn it. When I was a TA for calculus, most of my students were pre-med, engineers, or in other sciences.
I've done work on fluid simulations. It sure would have been nice to understand the buttons being pushed so I can better validate what's going on.
And I think I did well in calculus. Just not "mastery of multi-variable calculus to transform fluid dynamics formulas into software" well.