I wonder why.

I wonder why… if an investor has owned a well located apartment building in Seattle and has experienced nearly crazy appreciation in value recently, though not necessarily cash flow, and is at an age that is probably the last ¼ of his life,  why not sell the great location building for a great price and trade that equity into a less well located property that is much bigger and trades at a much higher CAP rate?  Just for example:  sell the 25 unit Queen Anne property that is worth $7-8M but generating only $250,000 in cash flow and take the proceeds (via a tax-deferred exchange) and buy a 100 unit property in Eastern Washington that generates $640,000.  It seems to me that later in life one often cares more about cash flow than about appreciation and the delta in CAP rates between great located Seattle properties and stuff in Eastern Washington is huge.  The investor stays in the same investment type he likes but more than doubles his cash flow!  While this makes great sense to me I find few people willing to do this.