I used Delphi for more tan 10 years, so this is what I believe it went wrong: * They lost Anders Hejlsberg * Free compilers got aceptable. * Lack of back compatibility, new VCL components from one version weren't compatible with older ones, every new versión require to biy the new components. * To expensive. * No new books to learn Delphi, they are to old. I'm still using Delphi 7 for some projects.
Even after not using it for 10 years I miss Delphi a lot. You could click a UI together in a very short time, add some code and you had a running standalone .exe without the need of any runtime dlls. Yes, Delphi it was limited in some ways and the language was not the best, but is was (and in my opinion still is) the best way to easily create a "simple" standalone gui applications.
I currently miss the rapid development tools we had 15 years ago. There is definitely a need for a HTML5 RAD tool - ideally with the combined functionality of JetBrains WebStorm and Adobes Dreamweaver.