What is the average amount of time it takes to sell a Prop

There is a vacant Prop. on Wellington Rd Clayton, which has a “For Sale” sign since second week of Dec 2009, Which is almost 3 months by now, is that normal to take this long to sell the prop?

I wonder what could be the reason:

Vendor price expectation too high.
Buyers not interested in the prop/area.
interest rate can influence the sell time.
may be its SOLD but REA don’t want to remove the “for sale" sign from the Prop. which is a good publicity for REA company but they usually put big SOLD sticker on top of “for sale” sign.

In my opinion (may be wrong) If the property has the correct marketing and is priced right from the beginning then should sell within 2 months :confused: