The irony here is that other SOC/SBC makers are focused more on throwing a barely stable design onto AliExpress for $20 than investing in good upstream support that would allow them to charge a premium.
Raspberry Pi wasn't always able to charge a premium, that benefit came from years of investment into software and community. I have not yet seen another SOC vendor or board partner realize this in any significant way.
Besides the price, anyway.
This is their latest "High performance industrial grade embedded computer" that I can see on their website
Of course you'll have good upstream support for something as old as the i.MX6UL, it's been out for 8 years (7 years at the time they released the TS-7250-V3).
No wonder Raspberry Pi has upended the market, when a single core Cortex-A7 is the competition.
Even an Allwinner chip that has a terrible BSP at release has good upstream support 7 years later.
I disagree. The NXP (i.MX line) and the TI (am62x) and the STM32 MP1/2 all have good mainline support.
What you say is true of most of the Chineese chips and of mobile chips but if you go with mainstream suppliers targeting the industrial / automative markets these days mainline Linux support is good at the SoC level. At the SoM level some are better than others but it's not that hard to pull the approriate DTS into your mainline kernel build even if it isn't already upstream.
RPi is probably better for hobbyists but that's not due to the mainline status but a community more in tune with hobbyists than the more industrial products.
I've built professional embedded Linux systems based in i.MX5/6/8 and STM32MP1 with mainline based BSP rather than vendor stuff but have only ever used the RPi for one off tools.
ESP32/ESPHome may have taken over the lower end with its easy config but there's still no real Pi competitor. A decade after the first RPi release, I still dread using any other platform when I have to design a board that requires more compute than an ESP32.