Certainly possible, but the way the IP stack works, a properly designed Ethernet link will not transfer phase noise from its recovered clock to the stack’s higher level clocks, which ultimately send the data to the DAC. If the ethernet transceiver in your streamer is doing its job correctly, it should be (close to) immune to effects from a dirty input signal. I think that’s why I noticed no difference. Also, in my Streamer/DAC, the DAC uses its own clock to access data from the incoming data buffer, something that is not possible if your streamer is feeding the DAC by SPDIF.
I do believe that many of the audio companies who have put streamers into their DAC products don’t fully understand how to make sure the clock domains are properly isolated from each other, so these products may benefit significantly from a better switch. I think the following quote is indicative of this. If plugging an ethernet cable into your streamer degrades SQ even when the signal is wireless, your streamer definitely has clock domain isolation issues.