The Linux kernel is an easy example, sure, but it's not the only one. You can say the same thing about proprietary operating systems and software as well. It's been a long time since I've had misbehaving applications blue-screen Windows. That's something that used to happen
daily when I ran Windows 98. Or if you prefer MacOS, I remember MacOS Lion being incredibly unstable, with beach-balls and crashes galore. That's all been fixed.
Applications have gotten better too. Browsers have gotten significantly more robust against misbehaving pages. Microsoft Office doesn't eat my work (even if I forget to hit ctrl-s).
In fact, I would go so far as to say that the only software which has gotten worse is video games. Used to be you could put in a disc, install the game, and be reasonably assured that you were getting a playable final product. Today, you put in the disc, install the game, and then have to download multiple gigabytes of patches... and the game is still often buggy (Bethesda, I'm looking at you!).
>99.99999% of software in big corporations will not have even 5% of the quality of the Linux kernel.
That is true. But it was equally true when Linus Torvalds dropped the first version of the Linux kernel all the way back in '91. It's not clear to me that things have gotten worse since then.