[dangus]

Isn’t that true for most software though?

Gimp isn’t better than Photoshop.

LibreOffice isn’t better than Office.

Kdenlive isn’t better than DaVinci Resolve/Adobe Premiere/Final Cut Pro.

Heck, a whole lot of I know consider IntelliJ a whole lot better than VSCode.

Open source isn’t really guaranteed to compete with proprietary software and often doesn’t.

The author calls that fracture, but to me an open source product with extensions will logically have both proprietary paid extensions and open source extensions, just like there are vendors who sell closed-source software for Linux.

If I sell my proprietary application for Linux and I only distribute it for Ubuntu, that doesn’t make Linux “not really open source.”

In my opinion that is normal and expected and isn’t cause for alarm.

[kragen]

No, it isn't true for most software. Firefox and Chrome are better than MSIE or Spyglass Mosaic. TCP/IP is better than CompuServe, AOL, and X.25. Apache and nginx are better than IIS. Perl, Python, and JS are better than PowerBuilder and Visual Basic. GCC is better than Borland C++ and various Unix-vendor C compilers. Even today, GCC is an enormously better C compiler than Visual Studio's, although at least Visual Studio does have a competitive C++ compiler in it. Arduino is better, for most purposes, than various proprietary embedded-vendor IDEs, which themselves mostly use GCC. Linux is better than Unicos, Solaris, and Symbian, though iOS and Microsoft Windows are still competitive.

Open-source software has pretty comprehensively replaced proprietary software throughout the computing stack over the last 30 years mostly by being vastly better. Proprietary software is holding onto footholds in a few places, most of which you listed.

The general strategy for preventing the situation where "an open source product with extensions will logically have both proprietary paid extensions and open source extensions" is copyleft licenses such as the GNU GPL.