Many Linux distros have Power support; Ubuntu just added little endian ppc64 support for additional compatibility. JVM is available, and most other software. It is not that much work...
Sure, it's doable, I have a few ppc at home, but I know first hand stories of small/medium companies just not wanting to risk that.
They just have higher costs at maintaining some dependencies, custom builds etc. You never know when you will get some new version of something, like jdk8. Then you have things like missing Go compiler (yes there is gccgo for ppc but still not everything works the same).
It's perfect for enthusiast, it's ok for companies with strong investment in IT infrastructure. I just wonder what is the best way to convince those small companies that there is no problem. Perhaps the tools/distros etc are starting to mature at the right point and this will soon no longer be a big practical problem.
Having gone through a few architectures, I think the worst offenders is the huge area of undefined/unspecified behavior of C and C++ compilers where many developers assume their compiler behavior is part of the standard.
Other languages with more OS agnostic libraries tend not to suffer that much from porting issues except from bit fiddling code. There is however the availability issue as you mentioned.
