I'm sorry that no one seems to be able to answer the original question from the OP. My guess is that this is a similar situation to high end class D amps. Most of them are based on a few different amplification modules. Of course, different input buffers & power supplies (and occasionally more dramatic alterations) results in different sounding amplifiers, but the module used is often known and even touted,
Industry sources have suggested to the OP that most streaming is done via a few standard platforms. As with class D amps, additional circuitry before, after, and possibly even in those modules can result in different sounding streamers. Yet the identities of those common platforms is clearly not common knowledge.
It is possible that most/all "high end" streamers are the result of completely independent platform designs, and that the sources were referring to the multitudes of AV receivers, HT setups, etc. sharing "streamer on a chip"-type implementations. The real answer is probably more subtle.
Going back to class D amps, most of them are tucked away in cars, TVs, etc. and are probably not GanFet, Purifi, Hypex, ... They're based on anonymous, less carefully designed modules. It seems unlikely that every high end streamer shares no common circuitry/software, but none of us know if there is a "Hypex" of streamer platforms (not singling them out as best or worst, just noting that it's easy to find multiple well regarded amps using Hypex). Given that this is Agon, I believe the OP doesn't care whether all the streaming devices at Best Buy use the same -say- Samsung streamer. They're probably curious if there are reputable streamer platform modules being used in multiple high end devices, and who makes them.