Completely agree there is no grand conspiracy surrounding the standardization 440hz. Regarding the baroque era, this video explains a lot of the problems Bach and other composers dealt with because tunings so widely varied from place to place, and how 415hz really wasn't standard at all.
View: https://www.youtube.com/watch?v=LNkpWFL8XWA
And she doesn't even go into Werckmeister and the various competing temperaments of the time. Our ears have grown accustomed to the precision of almost two centuries of A440 and equal temperament. In the 16th century they were just doing what they could to get it close. Those baroque organs sound quite out of tune to our modern ears! I find it almost impossible to detach myself from this conditioning enough to appreciate such an instrument.
Going along with your liturgical music example, it also makes sense to me that a slightly higher pitch was agreed upon at a point in history when secular music had greatly eclipsed sacred music in the cultural zeitgeist. People go to the opera or symphony for excitement and stimulation - the opposite reason they go to church.
Thanks for adding valuable details to my somewhat rushed answer. I'll add another one: differences in pitch occurred as late as the 20th century. I was fortunate to learn and practice in a Feurich upright piano from the 1920s (?) tuned a whole half tone lower than 440 Hz. This was determined by the pianomakers. Thus, the perception of the western scale for a bunch of my family members who learnt in old pianos is consistent with mine and half a tone lower than "the standard'. When we are learning to play something by ear in a modern day piano, things get messy as we consistently hit the wrong keys!