I think it's not that people don't care and there are some projects (most relevant is probably coreboot) that try to replace firmware with free alternatives. It

I think it's not that people don't care and there are some projects (most relevant is probably coreboot) that try to replace firmware with free alternatives. It's just that this is a very hard problem. Basically everything these days can be its own computer, sd cards, hard discs, network controllers, ... Their inner working is usually not documented and often two revisions of the same product are different internally. And the lifetime of these devices is short. Projects that try to replace firmware on consumer hardware often have this problem that they spend a fair amount of work on something and once they have reasonable support the device is no longer sold (e.g. the rockbox project constantly strugles with this). I think the only possibility to have widespread free firmwares would be if this could be made a selling point for vendors. However to do that you'd need a widespread demand for these things, much larger than the open source / free software / hacker community is able to create right now. If it'd be considered "cool" to release the code of your firmware that could change things.