I stopped panicking years ago.
Why? Because I kept finding surprising examples of openness. I also have doubts that internally-divided, competitive organizations can maintain authoritarianism for long. In business particularly, authoritarianism is quick to evaporate when it gets in the way of profit. Consider Apple's changes over the years; switching from entirely closed firmware to OpenFirmware, adopting PCI and PCIe, and even switching to a nearly-standard PC platform. Note too the many contributions to open source by the worst of authoritarian companies -- Apple and Microsoft. I've also seen reverse engineering increase the more closed hardware appears.
I'm too short on sleep to write anything in-depth, but I think there's 2 issues facing us.
1) Rising complexity. This seems to be an inescapable part of increasing power, but is it? And how much power do you need for your OS, anyway? I remember Linux doing everything I wanted with 64MB RAM and a 120MHz Pentium pro. I can certainly get quite a lot of useful work out of that hardware or even much less, and I can both innovate and enjoy my hobby. This is practically embedded hardware level these days, and embedded hardware has to be documented for the developers. Of course, I've wanted more since that old Pentium; specifically 3D and video, and I've wished for 4k resolution. The situation with these features is less encouraging, but some video codecs are better than others and hardware support is possible.
2) The glacial but inevitable demise of the PC. This one might not even be real in the sense that the situation the PC created was never as good as it seemed. The very compatibility we blame for complexity has enabled a bloom of OS development as much more has been written about the PC than any other platform. Nearly all new OSs get written for the PC platform, but then we find they run only in a handful of emulators and maybe 1 or 2 very specific laptops. The PC's openness has enabled a profusion of perpherals which need different drivers, but even with as central a component as the BIOS, "Booting on one computer is easy; booting on many computers is hard." UEFI doesn't seem to be much better in that regard.
Also remember that the platform which is, for real, emerging as the "one true OS" is POSIX which is not owned by any one company.
On a related note, how many of us have full control of our Linux systems and still have time for OS development? I've resigned myself to maintaining "ugly boxes" with a black-box OS -- Linux counts as black-box in this context just as much as Windows and Android -- while developing and running more accessible and interesting systems on other hardware and emulators. The ugly boxes can handle all the 3D, video, and most of the high-quality font rendering I need.
I want to target hardware which users can readily and affordably obtain in consistent form. I'm not yet sure which hardware, from boards marketed to hobbyists to a custom PCB supporting one of those ARM+FPGA SoCs. 9front devs made their "aijuboard" around a Xilinx ARM+FPGA SoC which supported SATA, framebuffer graphics, real ethernet and of course USB, and that was 9 years ago now.
tl;dr: We can't have everything we wish for, but the situation's not all bad. There is plenty of opportunity for OS dev.