unfortunately it is complicated... the reason modular is more expensive is because manufacturing and logistics become much more difficult and they lose the opportunity to sell new phones every year claiming new features. it's a double loss for them.
our consumerist culture makes it difficult for people to realise this, but most of the time we are not paying the real cost of products (the modular question, also sustainability, ethical questions). we tend to complain about the expensive one, when the cheap one might be the one to blame because it's simply shifting the cost away from the companies and costumers.
if the market ever moves towards modular phones, hopefully a few years later you could be able to do that you're suggesting
been 6 years for me. it lasted a long time but their shadow fades away eventually. I'm living in peace now
stay strong, survivor