Comment by microtonal

Because most of them don't really design their own phones, but instead sell what (mostly Chinese) ODMs give them with some small customizations.

I don't know about ShiftPhone, but e.g. Volla just sells rebranded Daria and Gigaset phones, typically marked up by a few hundred Euros to sell some EU-made/privacy/degoogling dream. In reality they are just cheap phones that the ODM does not really care about with Linux kernel and firmware trees that haven't seen any (security) updates in years.