Lenses in high-end smartphone cameras are usually built by the phone manufacturers themselves. This is unlike other camera-related parts including sensors, which are built by OEMs. (Most of the high-end sensors are built by Sony.) They build lenses as a part of the case.

The lens design is so tightly coupled to the case that vendors cannot rely on the third party.

This is a fascinating fact for me. For standalone digital cameras, people are talking about lenses all the time. People agree that it is one of the most important pieces of a camera. On the other hand, people rarely mention lens quality when they talk about smartphone cameras.

Why?

One hypothesis is that lenses matter less on smartphone because it's so tiny. This doesn't make a lot of sense however, because everything is tiny on the smartphone camera, even the sensor, and people do care about the smartphone camera sensors. (Or maybe not: Some Samsung high-end phone has different sensors on different configurations but few people complain.)

Another possibility is that people don't care because they cannot swap them. Lenses can be interesting only when it is exchangeable, but this isn't case for smartphone cameras. This theory is a bit more convincing, but I'm still not so sure. Many fixed-lens compact cameras pitch their lenses. See the web page for LUMIX LX100 for example. They boast their LEICA lens.

Here is my argument: People don't talk much about the lens, just because the conversations around smartphone cameras are yet to be mature enough. Eventually someone will figure out how to evaluate and talk about the lens on phones in some interesting ways, and other people will follow. Once that happens, smartphone vendors will start using brand-named lenses on their phones, regardless of its contribution to the overall image quality.

One way to demonstrate the "raw" lens quality is to retrieve RAW format image from the camera, bypassing the post processing of the software stack. This still counts the quality of the sensor, but it'll also reveal more of the lens' characteristics.

Adobe's Lightroom for Android has a RAW camera feature and you can retrieve the RAW images from your phone using the app. You'll be surprised how noisy they are and will appreciate the power of the software stack. But if you have different phones, you can also compare the RAW images from them. It'll be an interesting experiment.