Google Chromecast Audio offered basic streaming support for $35, but didn't sell enough of them to justify keeping the product around. Most people that want this level of performance are satisfied with (and would prefer) built in streaming support in receivers, TVs, smart speakers, etc.
If you are talking about something that would be considered audiophile quality, then I think the Node 2i sets a good baseline. We might see a bit of price erosion, but it's more likely we'll see an incremental step up in performance from one generation to the next at roughly the same price point. This seems like a good sweet spot for an entry-level audiophile streaming product.
Like we've seen with DACs, amps, speakers, etc, I'm sure there will be companies that continue to push the envelop at the high-end. We already have the Innuos Statement at $15K and there probably others that are even higher which I haven't paid any attention to.