I've built a number of systems over the years, I'm not an equipment churner, rather system builder, so the following pattern repeated itself over the years. A series of upgrades resulting in marginal gains until system was completed. I considered a system completed when only minor tweaks left. I considered new speakers or amp to be the beginning of new system. So this pattern repeats itself a number of times over period of over twenty years.
Each successive build relies upon knowledge gained from building past systems, so marginal gains also experienced from one system to next, this means each successive system better SQ than previous systems.
So we come to present system, same pattern followed with far more attention paid to streaming setup vs. prior system where I first incorporated streaming into setup. The vast majority of changes I've made over past five years with this system have been streaming related which has resulted in the usual pattern of marginal gains. However with this system and more recent changes in streaming equipment there has been this breakthrough or surpassing of this certain plateau that has always existed for me with digital in general. The one purchase that took me over that plateau was my new custom build streamer with amazing LPS. Digital that now competes with the best vinyl setups I've heard in regard to ease, refinement, harmonic development was made possible by this single purchase. Certainly, all the marginal gains made by all the changes made prior made it possible, but the streamer made all the difference.
So, based on my experience obviously I'm going to judge streamer as the most important component in a streaming setup. Assuming one has a system capable of extracting max potential from a streamer, the streamer has become as important as amps and speakers in my calculations.