Techies (programmers) are very sensitive to the technology platform that they will be using on a job. These jobs are not generic. The language and the tools will place a long lasting imprint upon the developer.
So suppose such an outfit were to locate a good (qualitatively) person who could help them, but who wasn't into Delphi at the time? That person would have to assess their career interests in spending the next 2-5 years in bed with Delphi.
My bet is that most talented developers presented with such a choice would not take it. "Learning Delphi as a job benefit" isn't exactly a benefit, it's really a nail in the career coffin.
The only developers who would take such a job would probably do so out of desperation. And why are such people desperate? You have to ask that.
First you must decide if you want a life working 50 hours per week then after 30 years you find the CEO stole your pension. If so, follow the latest and greatest, filling your resume with all the buzzwords. Today and into the future programmers are labor, lower middle class labor! And that's OK for some.
But, if you want to be successful you can't follow the crowd, you have to go where the other guys aren't. I'm not saying go to Delphi or VS or any other IDE. I'm saying you're right about what happened with Delphi, but if you're gonna' be part of the success of a product not just hired hands. Then you'll pick the IDE that gets the product done quickly so that you can test the market.
VS became what Delphi was many versions ago. VS will catch up to Delphi in the near future. The Delphi paradigm is the future for successful developers, not laborers... developers. It doesn't matter if they use VS or Delphi the visual RAD approach will win. Why pay someone to re-code sorting and searching algorithms that have been coded a thousand times before when you can drop a component that does the sorting, the searching, and more?
The small companies you're describing failed because the market didn't take to their product. If it had they would have switch to any IDE needed to keep making money. The reason you're sore is you were labor and didn't end up with a lasting job. While the entrepreneurs of those companies probably bagged a chunk of change in the very beginning. But entrepreneurs don't reinvest, they grap their chunk as soon as possible and keep going only if they can find "other people's money" to use.