I mean KDE did take over the desktop, with most of our apps living in the browser and most of the browsers being based on their code.
With a product using code from KDE it must be said.
Two of three remaining relevant browser engine vendors (Apple and Google) base their browsers in that code base. They could have gone from scratch or used a different base, but they took KDE's. They wouldn't have if it was of bad quality and unmaintainable.