I'm a big sailer too. I used to crew on racing boats and classic schooners.
Let's say we have a cantilevered mast and can swap it out "quickly". For 2MW worth of generation that would be a massive engineering feat and would mean that you have inventory not being utilized stored in the warehouse. Not just a generator or blade, but an entire system unutilized sitting around! Also most sailing masts are fairly light (aluminium) and short (30'). A 2MW wind mast would be 10x a sailing mast and hold all of the generator and electronics, not just a hollow tube that needs to be structurally sound. also masts are designed to be rigid and are held in place using shrouds and stays. A wind mast designed to move can not be held in place using guy-wires as that defeats the purpose of the dynamic wind mast.
Workers on these wind farms are making between $10 and $25 each and every hour. Some specialized workers are making double that at times, but let's keep the average of $20/hr.
It doesn't make economical sense even if you didn't need a crane to swap it out. And yes you would need a crane as this would be a multi-ton structure.
The primitive model is a tabernacled mast on a sailboat.[1]
[1] http://imgur.com/XwMCxbv