Purism’s Librem 5 phone starts shipping—a fully open GNU/Linux phone (Ars Technica)

It's a stock TP-Link dongle that benefits from all the economies of scale during manufacturing, then reflashed and rebranded.
Of course it costs a bit more for that work but their price is pretty ridiculous.

However, for the main subject of the article, the Librem 5, economies of scale very much *are* relevant.

The I.MX8 is in a completely different market to the smartphone socs. It is designed for things like automotive use where the product lifecycles are much longer and the volumes lower (many people change phones every couple of years, cars far less often).
It is probably also less price sensitive, cars being far more expensive than phones.

However hope may come in the form of a slow down in the pace of development of smartphone devices. Already the core CPU capabilities are no longer improving exponentially with each product generation as they were a few years ago.

With break neck development speed and a product lifecycle of 2 years max getting the hardware properly supported upstream was well down the priority list for the manufacturers.
That may change in a slower paced market.

And even if the manufacturers don't change it will at least make reverse engineering more worthwhile if the results are going to be usable for years.