Why can't desoldering wick be used to desolder SMD?
Actually, it does work to a degree.  However, with multi-lead components you may need to get more of the solder off than the wick can pull - contacts perfectly seated on the PCB may have solder retention "pull" the rivals that of the wick.  Even a small chip resistor or capacitor can be difficult to non-destructively remove while heating with a single tip iron (and while destructively digging it off often works, you risk damaging the board).

Some options:


A hot air station is one of the best tools, cheap ones go for around $100 now.
There are also dual-tip tweezer irons for removing chip resistors/capacitors.  These cause less damage to surrounding components/housings than hot air may, so if you do a lot of analog prototyping where you are changing components values they can be worth the $50-60.
for a chip resistor/capacitor, you can try to add enough solder to bridge the component and thus heat both sides at the same time
sliding a fine wire under SMT IC leads can help you lift them one at a time - music wire from a hobby shop specializing in gram-class aircraft is ideal
low temperature solder is sold which alloys with the existing solder to lower its melting point, however the possible alloying elements are either extremely expensive or substantially more toxic than lead.


Even with many of the other methods for removal, you may end up reaching for the wick to clean up the pads before installing a replacement.