I'll agree with lines getting blurred. Sony in particular uses very similar tech these days across the range, so the capabilities of the phone sensors and the larger sensors aren't leagues apart anymore. And we are clearly in the realm of deminishing returns. The iPhone 15 Pro sensor seems to be within a half stop in terms of dynamic range compared to my old A7R for example, while the latest A7R IV has about a full stop advantage to the iPhone 15 Pro. If you're not doing a ton of stretching of shadows/highlights, it's going to be hard to see the difference. For me, it's the dark/read noise in smartphones that still bugs me, and limits how big I feel I could print photography. I do wonder what the quantum efficiency of these newer phone sensors is like. Good QE helps a lot to swamp out sensor noise.
From a technical perspective, there's still an advantage to dedicated cameras/sensors that aren't packed in so tightly that cooling needs to suffer/etc. But the regimes where it matters is more and more niche over time. Akin to how I used to need as much power in a computer as possible for my job, but now things have evolved enough that I can start weighing the cost/benefit of marginally faster build times vs the cost of the machines to deliver them. I can make trade offs in terms of hardware that weren't possible 20 years ago.
Although at least in Astrophotography, we're still fighting for every single electron of dark current and read noise. Sensors like the ones used in the MILCs are king there, although costs of telescopes and filters for large full-frame sensors keep APS-C king there. I just picked up a camera for astro using a variant of the sensor in the A7R IV, which is electronically cooled to control dark current, and it is a beast. But it's even more niche than a MILC.