Interesting. Do you mind if I ask what software (or category) have you bought if you don't trust proprietary software?

Games mostly, some photography RAW post-production applications, an Android language learning application for some African language... Things I'll take as finished products and for which I accept giving up even the pretence of control - same as third-party services actually. Opposite would be anything I consider infrastructural - such as operating system or messaging.

When free competitive alternatives lack, I also accept some proprietary drivers. Considering how the industry moves towards managed hosting ("cloud") and how ridiculous it makes my old under-utilized family & friends servers look, I'm thinking that, confidentiality issues aside, I could accept what is standardized enough to transparently swap providers - the way my Internet access is wholly in hands of an access provider that I can swap by plugging another one in a free RJ-45 port on my border router (with no perceptible impact because I use none of their bundled services), or the way my domain names are in the hand of a perfectly replaceable registrar.

For me, I'll use the best tool for the job, whether it's FOSS or not. If someone built a great FOSS DAW, then I would definitely switch away from Ableton, Reaper, Logic etc. Until then, I'll use whatever gets the job done in the best way possible. It isn't necessarily about trust.

Out of curiosity, when was it the last time you checked on Free audio production tools? I know I didn't check for a while and was pleasantly surprised with the state of the current stack.

I'm not sure what the parent had on their mind, but the majority of people are forced to buy proprietary software coming bundled with hardware, like the BIOS, CPU microcode, graphics or network card firmware.