The people that seek out Mac-only software may have dwindled, but from the mid-90's through the 2000's there was a lot of pride in how Mac software looked and felt way better than other OSes.
When you have cross-platform software, even with a large dev team, there has to be huge compromises. For example, do menus go at the top (macOS) or do you have menus on each window (Windows)? Does Quit go under "File" (Windows) or under the app name's menu (macOS)? If you look at the Google apps on the iPhone, they originally looked like native iPhone apps, but since then Google apps look and work the same between OSes. This makes sense for a branding and development perspective. The few users who switch platforms for whatever reason are pleased, but for people who just use a Mac don't care about other platforms and want all their Mac software to look and work the same. Some people use Safari just because it's a native Mac app. Many people used Camino for that reason, too (Camino was a native Mac browser using Mozilla's Gecko engine developed between 2002-2012, first released a year before Safari).
As an extreme example, personally, I avoid almost all Java apps. Yes, they're cross platform, but they're ugly, slow, and usually integrate poorly with the rest of my system. JetBrains apps are the only exception that come to mind.