Oh that's not true. I would actually purchase in those outer areas you are fond of talking about - but only as a developer where I can buy it for $10 per acre and sell it to first-home buyers et al for $500 per sqm. Otherwise it makes no sense
It is coming across like you only invest based on "where you would live" type emotional assessment, whether intended or not.
It makes a lot of sense for people who dont necessarily have a high income to invest in higher yielding areas to make it easier to manage holding costs. The whole that is a crap suburb and therefore a bad investment outlook some people hold(not necessarily saying you do, but it comes across that way) is naive and based on emotion and snobbery not financial analysis.
I live in a fairly expensive inner/middle eastern suburb but chose to invest in the lower end, doesn't stop me buying more due to cashflow shortages of lower yielding areas. There are + and - to any investment strategy or any decision in life for that matter.
Eg Carlton - good area, higher entry price, higher holding costs, higher stamp duty to enter, higher risk if vacancy occurs. Less hassle, one property to manage.
Eg Melton - average to lower area, lower entry point, lower holding costs, lower stamp duty(if buying 3 houses for $750K vs 1 for $750K) lower risk to income -ie spread across three properties, easier to liquidate without selling all - lower end more buyers etc.
So when you dismiss an area or investment based on the area alone, expect it to be challenged on here, cause a lot of folks on here invest based on financial criteria not preconceived judgements