A few reasons. First, banks apply a different affordability criteria when it comes to mortgage. So just because you can afford rental of R9k doesn’t necessarily mean you can get a mortgage for lower. An estate agent doesn’t use same metrics as a bank. Second some just don’t want the burden of a 20 year mortgage; third some don’t have stable jobs that make them able to enter into a long term mortgage contract; so yeah different strokes for different folks 😀