Is buying a rental investment property with an existing tenant sensible?

My wife has a bee in her bonnet about buying a single rental property for retirement income – I suspect Kiritani San must have tweeted about this – but I think buying a 10 million yen or under one room in the Osaka suburbs is just one dead boiler (or renter…) away from destroying any profitability, and a NISA REIT is much more predictable. Also, if there was a reasonable profit to be made, wouldn't Estate Agents have already scored up the place?

What's the general opinion here? Note I have zero DIY skills so even simple maintenance would be contracted out, as would probably everything else be, so that would be a few percent off the top.

by KenYN