Unimportant tangent, but I think FireMonkey is a terrible name for a UI framework. I don't know why, but I hate it.
I think it's quite an accomplishment to survive in the modern world of free software development tools.
Quite a few years ago I worked at a company using Delphi, and judging by their homepage they are still using it. A company making industrial machinery, with a tiny internal software department for the software for provisioning and maintaining the machines, as well as the control room software. Usability and development velocity is more important than looking hip, and easy access to hardware interfaces is paramount. And compared to developer salaries those license costs really aren't that bad
Also pretty common in enterprise tooling, which is the market of tools like Delphi.
The alternative is everyone getting surprised that their favourite free software development tools (only free thanks to VC money), eventually goes away.
So should be perfectly enough for hobbyist.
It feels more stable and mature than most other languages. I do not know if there are enough developers keeping it alive, but hopefully it will mostly get bug fixes and ports to new platforms. Better if they do not mess with the language or standard libraries. Those that want a programming language that keeps breaking backwards compatibility every few months have plenty to choose from already.
Lazarus is a pretty sweet solution on Linux (or Codetyphoon, if you want more out of the box components).
However both have limitations in more complex areas, such as rich text (html), data binding and targeting mobile and desktop with a mostly shared code-base.
Although .NET also follows along, pity that it took so many years for Microsoft to actually care about native compilation beyond NGEN.
Lazarus is free with no artificial limitations, for FreePascal: https://www.lazarus-ide.org/