

The thing is: As far as I could gather, they are planning make this in Spain, which - in addition to small scale production (you pay more per part if you order less) introduces higher wages (and costs due to different regulations etc.).
Would I like it to be cheaper? Yes. But ceteris paribus I would not trust them to make it if this where cheaper.
Regarding alternatives, postmarketOS and Mobian also work on old Android phones.
That’s the age of the design. If you look at first use (usually a year later), and then widespread use beyond flagship chips for big cores (2+ years later), you’ll end up with different dates. Not every core ARM puts out ends up being used in a ton of chips across SoC vendors, as some fare better in the trade-of between transistors and real world performance/energy efficiency than others. A76 is definitely popular, if you look at SoC out there. The RK3588(s) GPU was announced in 2021 and shipped in 2022 first - so it’s relatively new, as the SoC is also not that old: RK3588s was introduced in early 2022, and these days it has decent enough Linux support to start building a Linux-first product with it.
The issue for small companies like Liberux is that they
That narrows things down very much, and leaves a quite narrow chip selection. Another start-up with the same goal, dawndrums, are designing around the same chip for that very same reason.
If you are in doubt about how competent RK3588(s) is, look into the work that Lucie from MNT does - a lot of future product design is done on MNT hardware, these days powered by that very RK3588.