That analogy doesn't exactly work, pro cameras do two main things differently: They allow you to take shots you couldn't before (because of some extra feature) and they allow you to do it much more easily than before (because of much better ergonomics).
It's more like if you could solder and get excellent through-hole joints, but you just couldn't solder SMD at all until you got a better iron.
What exactly would you think a pro camera allows you to do? I have one (one that is 4-5 years older than my iPhone) and I am not sure there is a single thing it can do that I couldn't do with my iPhone12Pro or compact camera.
Having said that, these are the main things you get:
* One million times better image quality under all conditions (I am not kidding, iPhone12 Pro is an utter joke in every regard compared to unprocessed pro camera footage, even though its 4 years more recent and we don't even need to talk about professional editing here)
* 100 times faster shutter speeds and reaction times. I.e. when I press the button, the pro camera gets focus and makes the shot with virtually zero delay. I can get exactly the piece of action that I wanted. With the iPhone your only chance of capturing the right moment is video or live pictures. If things move fast, you won't be able to get any decent shot at it, but you can still get a blurry image of something :D.
* Superior auto-focus. There is almost no shot under any circumstance where the focus isn't lasered on the eye of people (video and stills) and I mostly shoot at 1.4f, because hell, why the heck would I spend 2000$ on a lens if I use anything but the widest aperture...
* That brings us to another point: Superior bokeh. The iPhone's Portrait modes is a nice gimmick, but that's pretty much it. It's physically incorrect and often looks hilariously wrong/off. Compare that to a 1.4f full-frame lens and be mind-blown...
* Many many features that make it much easier to do many things, but I can't recall anything that wouldn't be possible with the iPhone and manual editing.
All in all having a pro-camera did two opposite things for me:
* Make me not want to take pictures with the iPhone, because I know the pictures will look ugly and I won't even be able to get the shot I want
* Make me not want to take pictures with the pro camera, because I know I never have it with me when I need it and it weights like 10 kilograms lol.
BTW, one thing an iphone camera does very well is take pictures of documents. That's one thing my old 35mm AE1 couldn't because it could not focus up close without a special lens.
Before the phone cameras got good, I'd carry around a Minox because it would fit unobtrusively in my pocket.
One thing your iPhone camera can't do at all (as opposed to can, but worse) would be long range zoom - there's only so far that cropping and software cleanup can go.
Although I know there are aftermarket lens attachments for iPhones, so maybe you could. (Likewise maybe you could get proper bokeh with an aftermarket lens too)
It's more like if you could solder and get excellent through-hole joints, but you just couldn't solder SMD at all until you got a better iron.