I see the bills as a challenge. How boring would it not be if my sim lived in a huge mansion packed with all the most expensive stuff but had minimum income so the bills were almost zero? I rather like them to pay bills according to how they live their lives. Getting more expensive stuff indicates a higher economical status life including more expensive activities. I liked what someone said about higher insurance and also storage fee if keeping stuff in inventory.
Regarding RL, where I live we pay taxes based on both income and what we own, so I never actually questioned the bills in TS4. Except the butler charging when I don't play that lot, of course, but they are all fired by now :)
