Just my opinion but I think that when you consider purchasing expensive streamers you reach the point of diminishing returns quickly nowadays when compared to budget streamers.
Without a doubt a more expensive streamer is going to sound excellent and better than a budget streamer such as a Bluesound.
But unlike a lot of other audio gear where budget gear is just ok compared to its high price alternative, here you are talking the difference between great sound (Bluesound for instance) and excellent sound (high priced streamers).
I am definitely in the camp that the DAC is the most important part of a streaming set up.