Because eventually you will find they are not as great as you thought..Unless you just don't care that much..
Depends. All the things you mentioned, I don't consider a waste.
Drums like First Act, super cheap brass cymbals - yeah those things are a waste.
Plus, the fact that you consider Zildjian A's to be low end tells me your perspective is skewed. They have been a world standard professional cymbal for many years. Are there better or more unique cymbals? Absolutely. But to classify them as low end is just silly, IMO.