I agree with your sentiments on an open platform ultimately prevailing. The hardware is still not there yet for good AR glasses (IMO). The processing power, connectivity, power, displays, etc.... just can't be crammed into an almost invisible pair of glasses. You basically need to squeeze the equivalent of the latest apple watch into a form factor about the size of a stick of gum (cut in half length wise)....
It's a classic chicken and egg economic problem. BMW doesn't make the chips/electronics that support the 48V architecture - Bosch & Continental (with NXP/TI/Infineon/Renesas as their silicon suppliers) do and they're not going to support 48V unless ALL (or a significant majority) of the automakers will. So it's a game of chicken.
I designed some stuff along these lines 15 years ago. At that time, 12 volt stuff was not just available, it was available with great economies of scale and a huge range of options, off the shelf. You need an automotive-qualified relay? A light? A solenoid? A DC-DC converter module? A fan? You'd have 100 choices at 12v, 30 choices at 24v and 3 choices at 48v.
Can't believe that he kept going all these years since selling SoftAid. I have learned a ton from reading his books, articles back in the days of "Embedded Systems Programming" magazine, and the newsletter. I sent him an email earlier this year mentioning that he's the only person I've ever heard of triggering an EPIRB (https://en.wikipedia.org/wiki/Emergency_position-indicating_...) three times when not in an ocean race :-)
Yocto is overkill for a hobbyist. It's designed to help big companies build linux distributions for multiple platforms. It works great for companies like NXP that have the resources to devote to it, but it's a f&$cking bear to wrap your hands around if you just want to build linux for a single dev-board.
Buildroot is much smaller/simpler for hobbyists IMO.
NVidia's Jetson lineup is really a double edged (disingenuous IMO) sword. They provide some nice GPU/NPU power for AI stuff and a decent price and is great to play/learn with. However if you want to take a jetson to production you can't. They don't sell the bare SOC's and the modules have limits to how many you can buy. That jetson lineup is probably a 0.05% pimple on their balance sheet...
If you're looking to build a product using an embedded linux system you're better off just using an off the shelf SOM from an embedded board vendor like Toradex or Phytec (to name 2 - there are dozens out there). There are some quasi standards around compute modules now like SMARC and SODIMM where the vendors build little pcb's that contain the SOC, DRAM, PMIC and optional EMMC and WIFI. Then you just built a carrier board to breakout the IO like USB, UART, HDMI, MIPI DSI/CSI-2, etc.... The design/layout/validation of the SOC/PMIC/DRAM is the hardest part and unless you're shipping in volumes > 100ku annually you're probably better off outsourcing the SOM.
If you're just looking to learn then by all means give it a shot! Jay's article is a great primer in the basics but just know that all of those parts are pretty slow/old by today's standards. That article is 4 years old and even 4 years ago those parts were fairly slow/cheap/low-power/low-pincount relative to the SOT at the time.
The Toradex's, Phytec's, Boundary Devices, etc... of the world all do a decent job with their BSP's but just know that they pull from NXP's mainline BSP release so there is a lag in time from when NXP makes a new release. Sometimes they'll fork their own libraries which I've seen cause some problems with application level software from NXP.
