They should, but how's it going convincing others to think that way? I've been pleasantly surprised by how easy it is to get by without Google, and I'm thankful to Lineage, /e/, and Graphene for showing me I can. Doesn't change the fact that if I'm the only one in my friend circle using Signal, its futile. Doesn't change the fact that banks will not make massive changes to their app for the minority.
I agree with you that FOSS is better but you do get to a point that your phone is a brick when you make no compromises.