Not sure I understand the concern about access from “modern embedded devices”. Something like a Raspberry Pi, or really anything with a decent ARM processor, can easily handle TLS.
[0] https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...
Your link mentions global_ca_store but provides no guidance on how to effectively populate it. That's the problem.
Interestingly, providing a non-Tivo-ized system, e.g. one that allows connection to an arbitrary cloud server, requires even more work than just hardcoding in "your" CA certificates.
None of this is insurmountable, but it leaves devs pining for a pre-HTTPS world where you can just do a DNS lookup and send "GET / HTTP/1.0" and not have to worry about all the attack vectors that HTTPS protects against, as well as the ones that HTTPS opens you up to.
Current 32bits SoCs prolly sale for the same price as 16bits systems of a decade ago, so yes, they probably can handle HTTP. However, 8 and 16 bits microcontrollers with only a few kb of RAM/Flash are still made ("modernly"), sold and used - and those cannot handle HTTPS.