The native OS interfaces on popular platforms (Win32, Posix) were in C, so it would have always been a 2nd class citizen.
I believe that Delphi was already on a decline when Borland decided to self destruct.
On Win32, they had a tough time competing after VisualBasic v5.0, where Microsoft had a larger mind-share.
On Linux, I had hopes with the Kylix port, but it was abandoned by Borland.
Regarding Kylix, I would say it was badly managed from the start.
So yeah, eventually the way out for better Windows support was C++/MFC, as even Borland's C++ compilers had their own set of issues.
But, this is a big but, if Borland managed to push Delphi the same way Sun pushed Java, then I think the mindshare story would be quite different.
A memory safe programming language, with RAD tooling support, capable of system programming tasks with native executables.
If Borland hadn't mismanaged everything the way they did in the mid-90's, maybe C and C++ wouldn't have the spotlight they enjoy nowadays.