Sorry but this is wrong.
I occasionally drift outside of my "zone" very occasionally but my zone consists of German, estate or SUV, high spec, leather.
I would never sell an Astra or Fiesta with cloth seats.
You need to like what you sell imo, to some degree. That doesn't mean only sell what you really like but if you find small cars with cloth seats and no toys soulless (like I do) then don't convince yourself you can grow to like them. Fine, if you don't care, will sell anything, don't like cars, don't like driving etc then it doesn't matter. But to say niches only work if it's performance or exotic is wrong.
Lucas, if you hate manual cars, don't sell them. There's a garage local to me that has been going for 40 years, they only sell Automatics, only ever been Automatics, only ever will.
Follow your nose, as Mr Dealy says.
Which is why the internet is such a great invention when used properly. Last week I bought 4 cars, from Manchester, Mansfield, Wimbledon and Colchester. I was in my PJ's at the time.