Economy in TS4 - please, fix it!

Like I said, I think the system is flexible enough. If your sims work hard, be it in a career or collecting stuff all day why be angry with them for earning a lot of money? Your play choices made them rich and they should live an accordingly rich lifestyle. A sim who fishes every day is a fisherman, one who fishes once in a blue moon has fishing as a hobby. Limiting certain activities is not making the game harder but making choices for your sims. If you want items to be more expensive you can make them so by setting up an in game shop for this purpose. Think of it as an alternative to the in game flea market where you can buy items much cheaper. Really rich sims can start lots of businesses, you don't need to play them everyday (or at all if you don't like that aspect of gameplay), but it's something where you can realistically sink a lot of money, think of it as investing. For fun, you can visit these businesses with your other sims.