John - i think that report is a little - uh, sensationalist.
1) just because someone is retiring from their 40+ year job, doesn't mean they want to live in a makeshift coffin until they die. Not all BBs want to downsize to a 2x2 - in fact, the research just completed for the 80+ over55's development i'm involved with suggests that smaller plots of land andhouses inside large complexes are for those without friends looking to network (incl immigrants), those looking for a lock and leave setup for travel, those looking for communal facilities and the infirm.
2) i built one of two (currently) single stories this close to the beach. everything else around me is a 400sqm monster, mine is a humble (for this area) 250sqm single storey with a small yard and easy access to the beach, lever style door handles, stone benches, hobless showers, veggie patch, no steps, easy care front yard, brick and tile.....see where i'm headed? i'm going for the market appeal in 10 years' time.
3) invest where everyone else will want to live - i'd pick gooseberry hill as much as mosman park or burns beach - the value attributed to ocean views, inland views, river views and/or locations immediately around them will only increase in value as land releases like Banksia Grove are marketed more and more.
4) land - they aint making any more of it. if you want, try buying a Dx block with a well positioned front home and reno. Selling a Dx block to a half savvy retiree means cashback for them immediately. Or buy a Dx block and only build on one lot - leave the other as yard or tennis court.