You could do just that before. Cross compiling for ARM is an ancient, dark craft. All that changed for the better (and admittedly much better for the hobbyists) is getting prebuilt binaries in the major distributions.
Before pi & co, cross compiling was a black art. You often needed to build your own toolchain and the target environment were often not standardized either so you would need different compilers for each target.
Fast forward to today, you can apt-get cross-compilers and build tools.
While it was a hassle, you could use pre-built cross compilers on debian before the Pi came along, as I was in 2010/11. Multi-arch helped a lot when it was introduced too.
Fast forward to today, you can apt-get cross-compilers and build tools.