Why did Borland fail (2015)

There are many errors and omissions in the post, but the overall idea seems accurate in that continuing changes in operating systems and environments made it hard for Borland to stay ahead or even keep up.

I used compilers and IDEs from lots of compiler vendors around the time from Borland, Watcom, Symantec, Microsoft, and supporting products like Phar Lap memory extender.

Somehow the Borland products were convenient but always seemed a bit more hobbyest than professional. Oh yeah, the Brief text editor was also really popular around that time.

My favorites were MS C 4.0 with CodeView (text mode GUI and remote debugging from another computer) and later Visual C++ 5 then 6. I don't remember using VisualAge C++ so probably also used MS C++ compilers for OS/2 as well--yes they came on many floppies (5.25" or 3.5"). Typically beta compilers came with the beta OS/SDKs that had some new memory or threading model that needed some compiler support.

Despite the site where this question is posted: The products where good and finished. Ahead of time. No code, low code and more. 4gl was is called back then. It failed due to not embracing web development fast enough imho.