I would argue that audio production is the one area that Open Source truly excels in. I was very pleasantly surprised to find so many different tools available for audio production on Linux and the quality of the software.
Of particular interest is the JACK (JACK Audio Connection Kit) which allows multiple software products to communicate seamlessly with each other. You don't need to hope that your primary production tool supports your plugin or tool, only that it supports JACK. The rest is transparent and you'll find that because JACK has been around for so long that all the production tools you use will support it.
There is a very high quality open source multitrack recorder that is consequently used as a platform for a highly regarded commercial platform (Ardour/Harrison Mixbus). There are very capable MIDI sequencers with full feature sets and a veritable ocean of MIDI compatible synthesisers and effects generators. There are also a number of solid sequencers and loopers available as well.
Hardware wise, support is a mixed bag. On one hand, many sound interfaces do not have open drivers - but if you are selective then you can find very high quality interfaces with very good support. My experience with real-time kernels and PCI based sound cards (MAudio Delta 66's in this instance) allowed me to record at error free sub 3ms latencies with 24bit/96khz on much older hardware - something I couldn't even hope to achieve on other platforms.
The primary weakness in open source audio production is also a strength. The sheer diversity of production tools available makes developing an effective workflow a time consuming business and commercial offerings do have a much shallower learning curve. This isn't an issue if you are willing to invest a little time during the initial setup stages.
If you want to do open source audio production then there's absolutely nothing stopping you. Some might want to do this for ideological reasons (political or technical - they might want to extend the software), but others might not have any other option. Somebody from a poor community or in a third world nation might not have much trouble sourcing hardware capable of performing the job (donations etc.), but affording the software with the same level of features the open source solutions offer could be prohibitively expensive or it may be unavailable for other reasons (geo-blocking, donated commercial software is a very problematic area, etc.).